Advertisement

Intrahepatic cholestasis of pregnancy: molecular pathogenesis, diagnosis and management

      Cholestasis, or impaired bile flow, is one of the most common and devastating manifestations of hereditary and acquired liver diseases. Intrahepatic cholestasis of pregnancy (ICP) is a reversible form of cholestasis in late pregnancy, persisting until delivery. The first case of unexplained pruritus associated with visible jaundice appearing in the last trimester of pregnancy and clearing shortly after delivery was reported in 1883 (
      • Ahlfeld F
      Berichte und Arbeiten aus der Geburtshilflich-Gynäkologischen Klinik zu Gießen 1881-1882.
      ). The disease remained unnoticed and unnamed until the mid-1950s when the detailed clinical features were described by several Scandinavian clinicians [for a review, see (
      • Kreek MJ
      Female sex steroids and cholestasis.
      )]. Familial clustering and endemic occurrence of cholestasis of pregnancy strongly indicated a genetic basis. Recent progress in molecular dissection of bile secretion has led to the identification of several gene defects that cause cholestatic liver diseases. These genes are now being tested as candidate genes predisposing to cholestasis of pregnancy.
      The incidence of ICP in Europe is approximately 10 to 150 per 10 000 pregnancies (Table 1). For pregnant women with cholestasis, quality of life can be impaired by itching, jaundice and fat malabsorption, but the prognosis for the mother is good. In contrast, ICP is a condition with possible lethal outcome for the unborn child if not handled with care. The major consequences of ICP are premature births in 19 to 60% of affected pregnancies (
      • Bacq Y
      • Sapey T
      • Brechot MC
      • Pierre F
      • Fignon A
      • Dubois F
      Intrahepatic cholestasis of pregnancy: a French prospective study.
      ,
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ,
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ),a high rate of intrapartal fetal distress in 22 to 33% of deliveries (
      • Shaw D
      • Frohlich J
      • Wittmann BA
      • Willms M
      A prospective study of 18 patients with cholestasis of pregnancy.
      ,
      • Fisk NM
      • Bye WB
      • Storey GN
      Maternal features of obstetric cholestasis: 20 years experience at King George V Hospital.
      ), and stillbirths in 1 to 2% of ICP pregnancies (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ,
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ,
      • Alsulyman OM
      • Ouzounian JG
      • Ames-Castro M
      • Goodwin TM
      Intrahepatic cholestasis of pregnancy: perinatal outcome associated with expectant management.
      ,
      • Berg B
      • Helm G
      • Petersohn L
      • Tryding N
      Cholestasis of pregnancy. Clinical and laboratory studies.
      ,
      • Laatikainen T
      • Tulenheimo A
      Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy.
      ). In spite of these substantial risks, ICP is often neglected and treated expectantly, even in obstetric centers. It is therefore essential to increase interest in and knowledge of the disease, and to find a safe medical treatment that improves fetal outcome.
      TABLE 1Incidence of intrahepatic cholestasis of pregnancy (n per 10 000 pregnancies)
      • Bacq Y
      Intrahepatic cholestasis of pregnancy.
      CountryIncidenceTime of surveyReference
      Australia801964–1966
      • Kater RM
      • Mistilis SP
      Obstetric cholestasis and pruritus of pregnancy.
      1501968–1970
      • Steel R
      • Parker ML
      Jaundice in pregnancy.
      201965–1984(7)
      Bolivia9201976
      • Reyes H
      • Taboada G
      • Ribalta J
      Prevalence of intrahepatic cholestasis of pregnancy in La Paz, Bolivia.
      Caucasian780
      Aimara1380
      Canada101963–1976
      • Johnston WG
      • Baskett TF
      Obstetric cholestasis. A 14 year review.
      Chile15601974–1975(37)
      Caucasian1510
      Araucanian2760
      6501988–1990(5)
      China101950
      • Jiang ZH
      • Qiu ZD
      • Liu WW
      • Liu YH
      • Wang QN
      • Miao HZ
      • et al.
      Intrahepatic cholestasis of pregnancy and its complications. Analysis of 100 cases in Chongqing area.
      ,
      • Qiu ZD
      • Wang QN
      • Liu YH
      • Miao HZ
      Intrahepatic cholestasis of pregnancy. Clinical analysis and follow-up study of 22 cases.
      301981–1983(126)
      Finland1101971–1981(10,55)
      France201961–1973
      • Perreau P
      • Rouch R
      Ictere cholestatique recidivant de la grossesse.
      ,
      • Gagnaire JC
      • Descos L
      • Magnin P
      Signification du prurit au cours de la grossesse.
      601988–1989
      • Roger D
      • Vaillant L
      • Fignon A
      • Pierre F
      • Bacq Y
      • Brechot JF
      • et al.
      Specific pruritic diseases of pregnancy. A prospective study of 3192 pregnant women.
      Poland1201964–1966
      • Roszkowski I
      • Wojcicka J
      Jaundice in pregnancy. I. Biochemical assays.
      Portugal1001994–1997
      • Brites D
      • Rodrigues CM
      • van-Zeller H
      • Brito A
      • Silva R
      Relevance of serum bile acid profile in the diagnosis of intrahepatic cholestasis of pregnancy in a high incidence area: Portugal.
      Sweden1501971–1974(9)
      1001980–1982(9)
      USA101932–1960
      • Cahill KM
      Hepatitis in pregnancy.
      701977
      • Wilson BR
      • Haverkamp AD
      Cholestatic jaundice of pregnancy: new perspectives.

      Molecular Pathogenesis

      Hormonal factors: estrogens

      Genetic predisposition and hormonal factors play key roles in the pathogenesis of ICP. Evidence for a primary role of hormonal factors in ICP was provided by the following observations (
      • Kreek MJ
      Female sex steroids and cholestasis.
      ):
      • The disease starts in the last trimester which is the period of the highest hormone concentrations.
      • Twin pregnancies display both a higher incidence of ICP and more pronounced rises in hormone levels.
      • ICP resolves promptly after delivery, when levels of placental hormones return to normal.
      • In further pregnancies, ICP recurs in 45–70% of the patients.
      Estrogens, in particular glucuronides like estradiol-17β-D-glucuronide, were found to be cholestastic in animal studies where they diminished the uptake of bile acids at the basolateral membrane of hepatocytes. An increased permeability of tight junctions (
      • Forker EL
      The effect of estrogen on bile formation in the rat.
      ) and a decreased fluidity of the sinusoidal membrane (
      • Davis RA
      • Kern Jr., F
      • Showalter R
      • Sutherland E
      • Sinensky M
      • Simon FR
      Alterations of hepatic Na+,K+-ATPase and bile flow by estrogen: effects on liver surface membrane lipid structure and function.
      ) have been suggested as underlying mechanisms. Decreased membrane fluidity lowers the Na+/K+-ATPase activity (
      • Simon FR
      The role of sex hormones and hepatic plasma membranes in the pathogenesis of cholestasis.
      ), which results in a reduction of the sodium gradient that is necessary for the sodium-dependent bile acid uptake into the hepatocyte. However, these mechanisms may not be primary but secondary effects due to cholestasis (
      • Simon FR
      The role of sex hormones and hepatic plasma membranes in the pathogenesis of cholestasis.
      ,
      • Boelsterli UA
      • Rakhit G
      • Balazs T
      Modulation by S-adenosyl-L-methionine of hepatic Na+,K+-ATPase, membrane fluidity, and bile flow in rats with ethinyl estradiol-induced cholestasis.
      ).
      Bile secretion depends on the sequential action of several proteins responsible for the specific transport of the main components of bile, i.e. bile acids, other organic anions, phospholipids such as phosphatidylcholine (lecithin), and cholesterol. These translocating proteins are localized at the basolateral and canalicular membranes that are functionally and biophysically distinct domains of the hepatocyte plasma membrane (Fig. 1). In experimental cholestasis in rats, inhibition of basolateral bile acid transport proteins (Na+-dependent taurocholate cotransporting polypeptide, NTCP; organic anion cotransporting polypeptides, OATP) occurs at the transcriptional level (
      • Simon FR
      • Fortune J
      • Iwahashi M
      • Gartung C
      • Wolkoff A
      • Sutherland E
      Ethinyl estradiol cholestasis involves alterations in expression of liver sinusoidal transporters.
      ). Biliary excretion of estradiol-17β-D-glucuronide is performed by the canalicular multispecific conjugate export pump (multidrug resistance related protein, MRP2) which causes a trans-inhibition of the canalicular bile acid export pump (BSEP) (
      • Stieger B
      • Fattinger K
      • Madon J
      • Kullak-Ublick GA
      • Meier PJ
      Drug- and estrogen-induced cholestasis through inhibition of the hepatocellular bile salt export pump (Bsep) of rat liver.
      ). Furthermore, estradiol-17β-D-glucuronide suppresses the expression of MRP2 at the posttranscriptional level (
      • Trauner M
      • Arrese M
      • Soroka CJ
      • Ananthanarayanan M
      • Koeppel TA
      • Schlosser SF
      • et al.
      The rat canalicular conjugate export pump (Mrp2) is down-regulated in intrahepatic and obstructive cholestasis.
      ).
      Figure thumbnail gr1
      Fig. 1Schematic diagram of the hepatic metabolism of hormonal factors that contribute to intrahepatic cholestasis of pregnancy (ICP). Hepatic estrogen conjugates inhibit bile salt uptake via the Na+ -dependent taurocholate cotransporting polypeptide (NTCP) and organic anion cotransporting polypeptides (OATP). Estrogen-glucuronides are excreted via the multidrug resistance associated protein 2 (MRP2) into bile, where they trans-inhibit the bile salt export pump (BSEP). Key enzymes of the hepatic progesterone metabolism include Δ4-3-oxosteroid-5β(α)-reductase and 3α/β-hydroxysteroid-dehydrogenase, which convert progesterone to pregnanolone and pregnanediol. These metabolites are conjugated with sulfate, glucuronic acid, and/or N-acetylglucosamine. The export pump for sulfated progesterone metabolites is unknown but might be related to multidrug resistance associated proteins (MRP). Progesterone binds to and modulates the activity of the phosphatidylcholine translocase MDR3.
      Hepatic biotransformation of the major estrogen in pregnancy, estradiol, includes sulfation and glucuronidation (Fig. 1). These conjugation reactions are typical phase II detoxification reactions, which help to diminish the cholestatic effect of estrogens (
      • Meyers M
      • Slikker W
      • Vore M
      Steroid D-ring glucuronides: characterization of a new class of cholestatic agents in the rat.
      ). However, the estrogen conjugate that increases most in pregnancy, estriol-16α-D-glucuronide (
      • Adlercreutz H
      • Tikkanen MJ
      • Wichmann K
      • Svanborg A
      • Anberg A
      Recurrent jaundice in pregnancy. IV. Quantitative determination of urinary and biliary estrogens, including studies in pruritus gravidarum.
      ), was itself found to be cholestastic, at least in animals (
      • Vore M
      Estrogen cholestasis. Membranes, metabolites, or receptors?.
      ). Beside decreased biliary excretion of estrogen metabolites, impaired hepatic sulfation was observed in ICP patients, using a xenobiotic surrogate compound (
      • Davies MH
      • Ngong JM
      • Yucesoy M
      • Acharya SK
      • Mills CO
      • Weaver JB
      • et al.
      The adverse influence of pregnancy upon sulphation: a clue to the pathogenesis of intrahepatic cholestasis of pregnancy?.
      ).

      Hormonal factors: progesterones

      In the pathogenesis of ICP, progesterone metabolites seem to play an even more important role than estrogens (
      • Sjövall J
      • Reyes H
      Bile acids and progesterone metabolites in intrahepatic cholestasis of pregnancy.
      ). An early observation described the development of ICP-related symptoms after the administration of progesterone in a woman with a history of ICP (
      • Lutz EE
      • Margolis AJ
      Obstetric hepatosis: treatment with cholestyramine and interim response to steroids.
      ), and recent studies showed that progesterone treatment during the third trimester was associated with ICP (
      • Bacq Y
      Intrahepatic cholestasis of pregnancy.
      ). The profile of progesterone metabolites in plasma from patients with ICP is markedly different from that seen in normal pregnancy (
      • Sjövall J
      • Sjövall K
      Steroid sulphates in plasma from pregnant women with pruritus and elevated plasma bile acid levels.
      ,
      • Laatikainen TJ
      • Peltonen JI
      • Nylander PL
      Effect of maternal intrahepatic cholestasis on fetal steroid metabolism.
      ). It has been discussed whether the changes can be explained on the basis of cholestasis alone or by specific derangements of the reductive metabolism of progesterone or the sulfation of its metabolites. It is noteworthy that pregnant women with cholestasis due to viral hepatitis have a normal profile of steroid sulfates in blood (
      • Giusti G
      • Piccinino F
      • Ricciardi I
      • Delrio G
      • Sagnelli E
      • Manzillo G
      Abnormal steroid sulfate in plasma of women with intrahepatic cholestasis of pregnancy.
      ), suggesting that the typical pattern of sulfated progesterone metabolites may only be attributable to ICP.
      During pregnancy, 250 to 500 mg of progesterone are synthesized in the placenta per day. In the liver, progesterone is reduced to pregnanolone and pregnanediol (Fig. 1). Four different isomers, 3α/3β and 5α/5β, are formed, which are further metabolized by hydroxylation and conjugation with sulfate and glucuronic acid. Mono- or disulfated progesterone metabolites are the most prevalent steroids during pregnancy with plasma levels of 10 to 15 μmol/l (
      • Sjövall K
      Gas chromatographic determination of steroid sulphates in plasma during pregnancy.
      ). These compounds are substantially increased in patients with ICP, in particular the 3α,5α-isomers (
      • Sjövall J
      • Sjövall K
      Steroid sulphates in plasma from pregnant women with pruritus and elevated plasma bile acid levels.
      ,
      • Meng LJ
      • Reyes H
      • Axelson M
      • Palma J
      • Hernandez I
      • Ribalta J
      • et al.
      Progesterone metabolites and bile acids in serum of patients with intrahepatic cholestasis of pregnancy: effect of ursodeoxycholic acid therapy.
      ). The different ratio of 3α- and 3β-hydroxy steroids is most characteristic for ICP (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Profiles of bile acids and progesterone metabolites in the urine and serum of women with intrahepatic cholestasis of pregnancy.
      ). Both biliary and fecal excretion of sulfated and glucuronidated progesterone metabolites are decreased in patients with ICP (
      • Laatikainen T
      • Karjalainen O
      Exertion of progesterone metabolites in urine and bile of pregnant women with intrahepatic cholestasis.
      ,
      • Eriksson H
      • Gustafsson JA
      • Sjövall J
      • Sjövall K
      Excretion of neutral steroids in urine and faeces of women with intrahepatic cholestasis of pregnancy.
      ). Substantial amounts of sulfated progesterone metabolites in urine of pregnant women are additionally conjugated with N-acetylglucosamine (GlcNAc) (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Profiles of bile acids and progesterone metabolites in the urine and serum of women with intrahepatic cholestasis of pregnancy.
      ,
      • Meng LJ
      • Griffiths WJ
      • Sjövall J
      The identification of novel steroid N-acetylglucosaminides in the urine of pregnant women.
      ). The formation of these metabolites is selective for 7β-hydroxy bile acids such as UDCA (
      • Marschall HU
      • Matern H
      • Wietholtz H
      • Egestad B
      • Matern S
      • Sjovall J
      Bile acid N-acetylglucosaminidation. In vivo and in vitro evidence for a selective conjugation reaction of 7 beta-hydroxylated bile acids in humans.
      ), which is used to treat ICP (see below). GlcNAc-conjugates are also the major urinary metabolites of UDCA in health (
      • Marschall HU
      • Matern H
      • Wietholtz H
      • Egestad B
      • Matern S
      • Sjovall J
      Bile acid N-acetylglucosaminidation. In vivo and in vitro evidence for a selective conjugation reaction of 7 beta-hydroxylated bile acids in humans.
      ,
      • Marschall HU
      • Griffiths WJ
      • Gotze U
      • Zhang J
      • Wietholtz H
      • Busch N
      • et al.
      The major metabolites of ursodeoxycholic acid in human urine are conjugated with N-acetylglucosamine.
      ) and cholestatic liver diseases (
      • Lindblad A
      • Glaumann H
      • Strandvik B
      A two-year prospective study of the effect of ursodeoxycholic acid on urinary bile acid excretion and liver morphology in cystic fibrosis-associated liver disease.
      ) including ICP (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Profiles of bile acids and progesterone metabolites in the urine and serum of women with intrahepatic cholestasis of pregnancy.
      ).

      Genetic factors

      The incidence of ICP shows striking geographic and ethnic differences (Table 1). ICP is most common in Scandinavia and South America. The highest rates of ICP are detected in Chile (16%), especially in women with overt Araucanian Indian descent (28%) (
      • Reyes H
      • Gonzalez MC
      • Ribalta J
      • Aburto H
      • Matus C
      • Schramm G
      • et al.
      Prevalence of intrahepatic cholestasis of pregnancy in Chile.
      ). The heterogeneous incidence in women of different ethnic origin, familial clustering as documented in several pedigree studies (
      • Holzbach RT
      • Sivak DA
      • Braun WE
      Familial recurrent intrahepatic cholestasis of pregnancy: a genetic study providing evidence for transmission of a sex-limited, dominant trait.
      ,
      • Reyes H
      • Ribalta J
      • Gonzalez-Ceron M
      Idiopathic cholestasis of pregnancy in a large kindred.
      ), and higher incidences in mothers and sisters of patients with ICP (
      • Dalen E
      • Westerholm B
      Occurrence of hepatic impairment in women jaundiced by oral contraceptives and in their mothers and sisters.
      ,
      • Furhoff AK
      Itching in pregnancy. A 15-year follow-up study.
      ,
      • Hirvioja ML
      • Kivinen S
      Inheritance of intrahepatic cholestasis of pregnancy in one kindred.
      ) clearly indicate a genetic predisposition for ICP. A high prevalence of the HLA haplotype Aw31B8 in patients with ICP was found in one kindred (
      • Holzbach RT
      • Sivak DA
      • Braun WE
      Familial recurrent intrahepatic cholestasis of pregnancy: a genetic study providing evidence for transmission of a sex-limited, dominant trait.
      ), but could not be confirmed in a later study (
      • Hirvioja ML
      • Kivinen S
      Inheritance of intrahepatic cholestasis of pregnancy in one kindred.
      ). Thus, the genetic base of ICP is still under investigation.
      Current research on the pathogenesis of ICP focuses on two major questions: Is there a defect in transport proteins disabling the biliary excretion of physiologically occurring metabolites in pregnancy or do quantitatively or qualitatively abnormal metabolites inhibit otherwise normally working transport proteins? The increased amount of sulfated progesterone metabolites in plasma could, for example, saturate the maximal transport capacity of dedicated transport proteins. The search for a genetically defined aberration of structure or function of hepatic transport proteins in patients with ICP is motivated by recent progress in the molecular characterization of other cholestatic disorders (
      • Trauner M
      • Meier PJ
      • Boyer JL
      Molecular pathogenesis of cholestasis.
      ).
      In 1998, mutations in genes encoding biliary transport proteins were identified in patients with progressive familial intrahepatic cholestasis (PFIC) [for reviews see (
      • Oude Elferink RP
      • van Berge Henegouwen GP
      Cracking the genetic code for benign recurrent and progressive familial intrahepatic cholestasis.
      ,
      • Jansen PLM
      • Muller M
      The molecular genetics of familial intrahepatic cholestasis.
      )]. The first mutations were found in the gene FICI (Familial intrahepatic cholestasis 1). The defect is prevalent in two cholestatic disorders with quite different prognosis (
      • Bull LN
      • van Eijk MJ
      • Pawlikowska L
      • DeYoung JA
      • Juijn JA
      • Liao M
      • et al.
      A gene encoding a P-type ATPase mutated in two forms of hereditary cholestasis.
      ): patients with Byler's syndrome (PFIC type 1) develop liver cirrhosis in childhood, whereas in many patients with benign recurrent intrahepatic cholestasis (BRIC) no major complications occur. The gene FICI codes a P-type-ATPase that is expressed in the ileum and in large cholangiocytes. The protein may function as an aminophospholipid translocase and is supposed to play an important role in the enterohepatic circulation of bile acids.
      In patients with PFIC type 2, mutations of the hepatic canalicular bile acid translocase (BSEP) have been identified (
      • Strautnieks SS
      • Bull LN
      • Knisely AS
      • Kocoshis SA
      • Dahl N
      • Arnell H
      • et al.
      A gene encoding a liver-specific ABC transporter is mutated in progressive familial intrahepatic cholestasis.
      ). Patients with PFIC type 3 display mutations of the gene encoding the canalicular phosphatidylcholine translocase (Multidrug resistance gene 3, MDR3) (
      • De Vree JM
      • Jacquemin E
      • Sturm E
      • Cresteil D
      • Bosma PJ
      • Aten J
      • et al.
      Mutations in the MDR3 gene cause progressive familial intrahepatic cholestasis.
      ). In contrast to other types of PFIC, patients with PFIC type 3 are characterized by elevated serum γ-glutamyl transferase (γ-GT) levels, which are due to bile acid toxicity in phosphatidylcholine deficient bile.
      In mothers of patients with PFIC or BRIC, a higher incidence of ICP has been observed (
      • De Pagter AG
      • van Berge Henegouwen GP
      • ten Bokkel Huinink JA
      • Brandt KH
      Familial benign recurrent intrahepatic cholestasis. Interrelation with intrahepatic cholestasis of pregnancy and from oral contraceptives?.
      ,
      • Clayton RJ
      • Iber FL
      • Ruebner BH
      • McKusick VA
      Byler disease. Fatal familial intrahepatic cholestasis in an Amish kindred.
      ,
      • Whitington PF
      • Freese DK
      • Alonso EM
      • Schwarzenberg SJ
      • Sharp HL
      Clinical and biochemical findings in progressive familial intrahepatic cholestasis.
      ). This indicates that heterozygote mutations of hepatobiliary transport proteins predispose to ICP. This hypothesis is supported by the finding that in the family of a PFIC type 3 patient, six women with a history of ICP were heterozygous for the same deletion (1712delT) in the MDR3 gene (
      • Jacquemin E
      • Cresteil D
      • Manouvrier S
      • Boute O
      • Hadchouel M
      Heterozygous non-sense mutation of the MDR3 gene in familial intrahepatic cholestasis of pregnancy.
      ). In addition, DNA sequence analysis identified one woman with ICP and raised serum γ-GT, but with no known family history of PFIC, who displayed a missense mutation (C546A); fluorescence activated cell sorting and Western analysis demonstrated disruption of protein trafficking with a subsequent lack of functional protein at the cell surface (
      • Dixon PH
      • Weerasekera N
      • Linton KJ
      • Donaldson O
      • Chambers J
      • Egginton E
      • et al.
      Heterozygous MDR3 missense mutation associated with intrahepatic cholestasis of pregnancy: evidence for a defect in protein trafficking.
      ). However, the most prevalent defects in the majority of ICP patients remain to be defined. The close link between genetic and hormonal factors is corroborated by the finding that progesterone binds to and modulates the activity of MDR-translocases such as the phosphatidylcholin translocase MDR3 (
      • Debry P
      • Nash EA
      • Neklason DW
      • Metherall JE
      Role of multidrug resistance P-glycoproteins in cholesterol esterification.
      ).

      Exogenous factors

      Some characteristics of ICP suggest that in addition to hormonal and genetic factors, environmental and alimentary factors may increase the risk for ICP in predisposed women. This is indicated by the decline of ICP prevalence rates in Chile during the last decades (Table 1), and the fact that ICP recurs in less than 70% of pregnancies in multiparous women. It was also reported from Sweden, Finland and Chile, that the incidence of ICP is higher in winter than in summer (
      • Berg B
      • Helm G
      • Petersohn L
      • Tryding N
      Cholestasis of pregnancy. Clinical and laboratory studies.
      ,
      • Laatikainen T
      • Ikonen E
      Fetal prognosis in obstetric hepatosis.
      ,
      • Humberto R
      • Báez ME
      • González MC
      • Hernández I
      • Palma J
      • Ribalta J
      • et al.
      Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals in Chile.
      ). Therefore, exogenous factors may superimpose on the genetic predisposition and lead to manifestation of the disease. Some studies linked ICP to low serum selenium (Se) levels (
      • Humberto R
      • Báez ME
      • González MC
      • Hernández I
      • Palma J
      • Ribalta J
      • et al.
      Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals in Chile.
      ,
      • Kauppila A
      • Korpela H
      • Makila UM
      • Yrjanheikki E
      Low serum selenium concentration and glutathione peroxidase activity in intrahepatic cholestasis of pregnancy.
      ). Se acts as a cofactor of several enzymes in the oxidative metabolism in the liver but the role of Se in bile secretion has yet to be defined.

      Fetal pathophysiology

      The pathogenesis of stillbirths in ICP is not fully understood. Autopsies show signs of acute, lethal anoxia with petechial bleeding in pleura, pericard and adrenal glands, but no signs of chronic anoxia (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ,
      • Laatikainen T
      • Tulenheimo A
      Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy.
      ,
      • Reid R
      • Ivey KJ
      • Rencoret RH
      • Storey B
      Fetal complications of obstetric cholestasis.
      ). In ICP pregnancies there is a major increase in the incidence of meconium-stained amniotic fluid (
      • Shaw D
      • Frohlich J
      • Wittmann BA
      • Willms M
      A prospective study of 18 patients with cholestasis of pregnancy.
      ,
      • Fisk NM
      • Bye WB
      • Storey GN
      Maternal features of obstetric cholestasis: 20 years experience at King George V Hospital.
      ,
      • Reid R
      • Ivey KJ
      • Rencoret RH
      • Storey B
      Fetal complications of obstetric cholestasis.
      ), with stillborns often lying in heavily stained fluid (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ,
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ). However, fetuses of women with ICP have adequate birthweights for gestational age and normal Doppler umbilical artery velocimetry (
      • Zimmermann P
      • Koskinen J
      • Vaalamo P
      • Ranta T
      Doppler umbilical artery velocimetry in pregnancies complicated by intrahepatic cholestasis.
      ), suggesting that chronic placental insufficiency is not the primary cause of fetal death. Infusion of cholic acid to fetal sheep increases the incidence of meconium passage, indicating stimulation of colonic motility by bile acids (
      • Campos GA
      • Guerra FA
      • Israel EJ
      Effects of cholic acid infusion in fetal lambs.
      ). In experimental models, it has been shown that meconium can cause acute umbilical vein constriction and lead to a reduction in umbilical flow (
      • Altshuler G
      • Hyde S
      Meconium-induced vasocontraction: a potential cause of cerebral and other fetal hypoperfusion and of poor pregnancy outcome.
      ,
      • Altshuler G
      • Arizawa M
      • Molnar-Nadasdy G
      Meconium-induced umbilical cord vascular necrosis and ulceration: a potential link between the placenta and poor pregnancy outcome.
      ).
      During ICP there is an increased flux of bile acids from the mother to the fetus, as indicated by increased bile acid levels in amniotic fluid (
      • Brites D
      • Rodrigues CM
      • Cardoso M da C
      • Graca LM
      Unusual case of severe cholestasis of pregnancy with early onset, improved by ursodeoxycholic acid administration.
      ,
      • Heikkinen J
      • Maentausta O
      • Tuimala R
      • Ylostalo P
      • Janne O
      Amniotic fluid bile acids in normal and pathologic pregnancy.
      ), cord plasma samples (
      • Laatikainen TJ
      Fetal bile acid levels in pregnancies complicated by maternal intrahepatic cholestasis.
      ), and meconium (
      • Rodrigues CM
      • Marin JJ
      • Brites D
      Bile acid patterns in meconium are influenced by cholestasis of pregnancy and not altered by ursodeoxycholic acid treatment.
      ). Because the high bile salt levels were found to be associated with more frequent occurrence of fetal distress (
      • Laatikainen TJ
      Fetal bile acid levels in pregnancies complicated by maternal intrahepatic cholestasis.
      ), this might be of great relevance for fetal prognosis, although the pathophysiological mechanisms have yet to be defined. Bile acids have been shown to induce vasoconstriction of human placental chorionic veins in vitro (
      • Sepulveda WH
      • Gonzalez C
      • Cruz MA
      • Rudolph MI
      Vasoconstrictive effect of bile acids on isolated human placental chorionic veins.
      ).
      Fetal bile acid balance is dependent on the placental transfer capacity for bile acids. Recently, in vesicle preparations of the basal (fetal) and apical (maternal) trophoblast membranes from patients with ICP, a diminished placental transport of bile acids was observed. This is supposed to result in decreased fetal elimination and a retention of toxic bile acids in the fetus (
      • Serrano MA
      • Brites D
      • Larena MG
      • Monte MJ
      • Bravo MP
      • Oliveira N
      • et al.
      Beneficial effect of ursodeoxycholic acid on alterations induced by cholestasis of pregnancy in bile acid transport across the human placenta.
      ,
      • Macias RI
      • Pascual MJ
      • Bravo A
      • Alcalde MP
      • Larena MG
      • St - Pierre MV
      • et al.
      Effect of maternal cholestasis on bile acid transfer across the rat placenta-maternal liver tandem.
      ).

      Symptoms

      In the past, icterus was believed to be the major clinical finding in ICP. However, the most common symptom is severe pruritus, which most typically appears in the third trimester and starts in palms and soles. In 10% of the patients, pruritus develops in the first trimester and 25% of the patients present with pruritus in the second trimester (
      • Huchzermeyer H
      Leber und Schwangerschaft.
      ). The pruritus is generally more severe at night and can lead to considerable discomfort for the patients. Only 10% of the patients with pruritus develop icterus (
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ). Thus, the old term pruritus gravidarum designates the mild course of ICP, whereas icterus gravidarum describes the aggravated course of ICP. Icterus without pruritus is rare. In most patients, pruritus and icterus disappear promptly after delivery, within 1–2 days; sometimes pruritus persists for 1–2 weeks. However, some cases with a protracted course of the disease have been reported (
      • Olsson R
      • Tysk C
      • Aldenborg F
      • Holm B
      Prolonged postpartum course of intrahepatic cholestasis of pregnancy.
      ). Four Puerto Rican sisters had recurrent prolonged cholestasis of pregnancy, which was followed by periportal fibrosis or cirrhosis but was most likely not identical to “classical” ICP (
      • Leevy CB
      • Koneru B
      • Klein KM
      Recurrent familial prolonged intrahepatic cholestasis of pregnancy associated with chronic liver disease.
      ). This study indicates that patients with prolonged cholestasis during pregnancy should be monitored for evidence of chronic liver disease, should be counseled on the risks of disease recurrence and progression in future pregnancies, and should inform family members at risk of the disease and its possible symptoms.
      ICP may rarely cause steatorrhea with decreased absorption of fat-soluble vitamins and weight loss. In cases with severe steatorrhea, increased intra- and postpartum hemorrhage may occur if the patient is not supplemented with adequate doses of vitamin K before delivery. Abdominal pain or fever are not observed, unless ICP is associated with other diseases like urinary tract infection.
      ICP is associated with a predisposition for cholesterol gallstones, and the incidence of ICP is higher among gallstone patients (
      • Samsioe G
      • Svendsen P
      • Johnson P
      • Gustafson A
      Studies in cholestasis of pregnancy. V. Gallbladder disease, liver function tests, serum lipids and fatty acid composition of serum lecithin in the non-pregnant state.
      ,
      • Glasinovic JC
      • Valdivieso V
      • Covarrubias C
      • Marinovic I
      • Miquel JF
      • Nervo F
      Pregnancy and gallstones.
      ,
      • Furhoff AK
      • Hellstrom K
      Jaundice in pregnancy. A follow-up study of the series of women originally reported by L. Thorling. II. Present health of the women.
      ). Primigravidae with ICP have a 2.7-fold increased risk for gallstones compared to pregnant women without cholestasis (
      • Glasinovic JC
      • Valdivieso V
      • Covarrubias C
      • Marinovic I
      • Miquel JF
      • Nervo F
      Pregnancy and gallstones.
      ). Both fasting and postprandial gallbladder volumes are increased in ICP (
      • Kirkinen P
      • Ylostalo P
      • Heikkinen J
      • Maentausta O
      Gallbladder function and maternal bile acids in intrahepatic cholestasis of pregnancy.
      ,
      • Ylöstalo P
      • Kirkinen P
      • Heikkinen J
      • Maentausta O
      • Jarvinen PA
      Gall bladder volume and serum bile acids in cholestasis of pregnancy.
      ). This increase indicates gallbladder hypomotility, which is believed to result from cholesterol absorption by the gallbladder wall (
      • Apstein MD
      • Carey MC
      Pathogenesis of cholesterol gallstones: a parsimonious hypothesis.
      ). Interestingly, the ICP candidate genes discussed above have also been established as genetic determinants for cholesterol gallstone disease in animal models (
      • Lammert F
      • Carey MC
      • Paigen B
      Chromosomal organization of candidate genes involved in cholesterol gallstone formation: a murine 'gallstone map'.
      ).

      Diagnosis

      Liver function tests are to be performed in every pregnant woman who experiences pruritus. The increase of serum bile acids in combination with typical pruritus is highly suggestive of the diagnosis of ICP.
      Among standard liver tests, alanine transaminase (ALT) is a very sensitive parameter for ICP (
      • Bacq Y
      • Sapey T
      • Brechot MC
      • Pierre F
      • Fignon A
      • Dubois F
      Intrahepatic cholestasis of pregnancy: a French prospective study.
      ). Serum transaminase levels are normal until delivery in healthy pregnancies and therefore, any rise should alert and lead to further tests. ALT is released into the blood in increasing amounts when the liver cell is damaged (
      • Pratt DS
      • Kaplan MM
      Evaluation of abnormal liver-enzyme results in asymptomatic patients.
      ). It has been reported that 20–60% of women with pruritus and elevated serum bile acid levels have 2–10-fold rises in transaminases (
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ,
      • Jeppsson S
      • Laurell CB
      • Rannevik G
      Plasma proteins after use of estrogen and-or progestogen in women with and without recurrent cholestasis during previous pregnancies.
      ,
      • Lunzer M
      • Barnes P
      • Byth K
      • O'Halloran M
      Serum bile acid concentrations during pregnancy and their relationship to obstetric cholestasis.
      ), but there is poor correlation between the levels of serum bile acids and transaminases (
      • Laatikainen T
      • Hesso A
      Determination of serum bile acids by glass capillary gas-liquid chromatography.
      ,
      • Laatikainen T
      • Ikonen E
      Serum bile acids in cholestasis of pregnancy.
      ).
      The most sensitive indicator for ICP is a rise of serum bile acid levels (Table 2). In healthy pregnancies, total serum bile acids are slightly higher in pregnant (6.6±0.3 μmol/l) than in non-pregnant woman (5.7±0.4 μmol/l) (
      • Brites D
      • Rodrigues CM
      • Oliveira N
      • Cardoso M
      • Graca LM
      Correction of maternal serum bile acid profile during ursodeoxy-cholic acid therapy in cholestasis of pregnancy.
      ), and levels up to 11.0 are accepted as normal in late gestation (
      • Carter J
      Serum bile acids in normal pregnancy.
      ). It is important to emphasize that the average value for total serum bile acids in ICP patients in Table 2 is a consequence of cases with more serious illness; in fact, a number of patients with markedly lower concentrations have been reported (
      • Bacq Y
      • Sapey T
      • Brechot MC
      • Pierre F
      • Fignon A
      • Dubois F
      Intrahepatic cholestasis of pregnancy: a French prospective study.
      ,
      • Laatikainen T
      • Tulenheimo A
      Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy.
      ). In ICP, glycine- or taurine-conjugated bile acids, in particular taurocholate, increase by 2- to 5-fold (
      • Sjövall K
      • Sjövall J
      Serum bile acid levels in pregnancy with pruritus (bile acids and steroids 158).
      ,
      • Bacq Y
      • Myara A
      • Brechot MC
      • Hamon C
      • Studer E
      • Trivin F
      • et al.
      Serum conjugated bile acid profile during intrahepatic cholestasis of pregnancy.
      ), with an increased cholic acid/chenodeoxycholic acid (CA/CDCA) ratio of approximately 4:1 (
      • Heikkinen J
      Serum bile acids in the early diagnosis of intrahepatic cholestasis of pregnancy.
      ). In normal pregnancies of the same gestational age as well as in non-pregnant women, the CA/CDCA-ratio is 1.5 (
      • Heikkinen J
      Serum bile acids in the early diagnosis of intrahepatic cholestasis of pregnancy.
      ). The abnormally high ratio in ICP patients might reflect the fact that the less polar bile acid CDCA is preferably sulfated and excreted in the urine. Both in women with ICP and in women with healthy pregnancies, the serum bile acid composition shows a marked predominance of CA and is similar to the biliary bile acid composition, in contrast to bile of non-pregnant women (
      • Laatikainen T
      • Lehtonen P
      • Hesso A
      Biliary bile acids in uncomplicated pregnancy and in cholestasis of pregnancy.
      ). The measurement of bile acid concentrations in serum is particularly helpful in pregnant women with pruritus but normal transaminases. The urinary bile acid excretion is increased approximately 10-fold during ICP (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Profiles of bile acids and progesterone metabolites in the urine and serum of women with intrahepatic cholestasis of pregnancy.
      ).
      TABLE 2Laboratory findings in intrahepatic cholestasis of pregnancy
      • Van Dyke RW
      The liver in pregnancy.
      TestNumber of patientsPercent of women with abnormal valuesAverage valueMaximum value
      Alanine transaminase321552.2±1.6 μkat/l (131±96 U/l)17.2 μkat/l (1030 U/l)
      Aspartate transaminase409602.0±0.9 μkat/l (119±51 U/l)12.3 μkat/l (736 U/l)
      Alkaline phosphatase575702.4±1.1 μkat/l (146±66 U/l)12.5 μkat/l (750 U/l)
      Bilirubin5582517 μmol/l (1.0 mg/dl)315 μmol/l (8.4 mg/dl)
      Bile acids1289047 μmol/l430 μmol/l
      Cholic acid647017 μmol/l109 μmol/l
      Total serum alkaline phosphatase (ALP) levels rise slightly in normal pregnancies due to high production of placental and bone isoenzymes (
      • Wolf JL
      Liver disease in pregnancy.
      ). ALP levels are usually elevated in ICP patients (Table 2), but are of poor diagnostic value. γ-GT, which is generally lower in late pregnancy, is usually normal or slightly elevated in ICP. If γ-GT levels are high, mutations in the MDR3 gene are suspected, but not routinely tested to date. Hyperbilirubinemia, up to 100 μmol/l (5 mg/dl) is only detected in 10–20% of the cases (Table 2). In urine, bilirubin and urobilinogen can be tested positive.
      Serum protein electrophoresis reveals slightly decreased albumin, whereas α2-globulins are moderately and β-globulins appreciably increased (
      • Forkman B
      • Ganrot PO
      • Gennser G
      • Rannevik G
      Plasma protein pattern in recurrent cholestasis of pregnancy.
      ). The increase of LDL-cholesterol and triglycerides, which is observed during pregnancy, is more pronounced in cholestatic patients including ICP, whereas HDL-cholesterol may decrease (
      • Huchzermeyer H
      Leber und Schwangerschaft.
      ). Cholestasis is associated with the appearance of the abnormal lipoprotein X (LpX) in plasma. LpX are 40–100-nm vesicles, which contain unesterified (free) cholesterol. Using mice with a disrupted Mdr2 gene (murine homolog of MDR3), Oude Elferink et al. (
      • Oude Elferink RP
      • Ottenhoff R
      • van Marle J
      • Frijters CM
      • Smith AJ
      • Groen AK
      Class III P-glycoproteins mediate the formation of lipoprotein X in the mouse.
      ) demonstrated that the appearance of LpX is dependent on the presence of the canalicular translocator for phosphatidylcholine (MDR2) and that abnormal excretion of biliary vesicles into blood occurs during cholestasis.
      An upper abdominal ultrasound is considered in ICP patients with abdominal symptoms or puzzling laboratory controls. Liver biopsy in general is unnecessary. Histology would show mild focal irregular intrahepatic cholestasis with bile plugs in the canaliculi and small amounts of bile pigment in centrilobular hepatocytes and macrophages. Necrosis or inflammation is absent. Electron microscopy revealed dilated bile canaliculi and loss of microvilli as well as mitochondrial alterations, including enlargement, irregular shape, and lamellar inclusions (
      • Adlercreutz H
      • Svanborg A
      • Anberg A
      Recurrent jaundice in pregnancy. I. A clinical and ultrastructural study.
      ).

      Differential Diagnosis

      The main differential diagnoses of pruritus of ICP without icterus are skin diseases, allergic reactions and pruritus related to abdominal striae. Only 0.07% of all pregnant woman develop visible icterus (
      • Schmid R
      • Haemmerli UP
      Der Schwangerschaftsikterus.
      ). The clinician distinguishes icterus in graviditate, the coincidence of icterus and pregnancy, from icterus e graviditate as a specific complication of pregnancy (Table 3). The acute fatty liver of pregnancy presents with transaminases up to 12 μkat/l (500 U/l), severe hypoglycemia, hepatic encephalopathy, and beginning disseminated intravascular coagulation. Pre-eclampsia is characterized by hypertension and proteinuria, and severe forms can be complicated by the HELLP-syndrome, which is defined by hemolysis, elevated liver enzymes, and low platelet count. The rise of transaminases is lower than in viral hepatitis and bilirubin is usually normal. In patients with high transaminases and/or high bilirubin, acute viral hepatitis, choledocholithiasis and toxic hepatitis are to be excluded. A high and rapid increase of transaminases favors acute viral or toxic hepatitis. Bile duct obstruction causes an increase in γ-GT and ALP, and abdominal sonography confirms the diagnosis. If cholestasis and elevated transaminases persist for more than 4 weeks after delivery, chronic liver diseases like primary biliary cirrhosis have to be ruled out by testing for antimitochondrial antibodies (AMA) and liver biopsy.
      TABLE 3Differential diagnosis of intrahepatic cholestasis of pregnancy (ICP) with jaundice
      • Schmid R
      • Haemmerli UP
      Der Schwangerschaftsikterus.
      EtiologyPrevalence (%)
      Icterus e graviditate
      ICP21
      Acute fatty liver of pregnancy
      HELLP syndrome5
      Hyperemesis gravidarum6
      Icterus in gravididate
      Viral hepatitis42
      Steatohepatitis
      Septic pyelonephritis
      Hyperbilirubinemia syndromes
      Drug icterus
      Bile duct obstruction6
      Hemolytic icterus4
      Metabolic diseases

      Management

      ICP is a fairly common disease with a high impact on fetal morbidity and mortality, and it is also a condition of great discomfort for the patients. Obstetric management of patients with ICP varies widely over the world. In spite of numerous reports of increased fetal risk (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ,
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ,
      • Reyes H
      • Simon FR
      Intrahepatic cholestasis of pregnancy: an estrogen-related disease.
      ) many obstetric clinics still choose to manage ICP pregnancies expectantly. Many different protocols for intensified surveillance have been proposed. It has been shown that a regimen including weekly fetal cardiotocographic (CTG) monitoring from the 34th week of gestation and induction of labor in the 38th week of gestation in mild cases, and in the 36th week of gestation in severe cases can reduce perinatal mortality to control levels (
      • Rioseco AJ
      • Ivankovic MB
      • Manzur A
      • Hamed F
      • Kato SR
      • Parer JT
      • et al.
      Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
      ). Another group (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ) reported reduction of perinatal mortality by active management (including amnioscopy and generous induction of labor) to one third, compared to expectant management without fetal monitoring (
      • Fisk NM
      • Storey GN
      Fetal outcome in obstetric cholestasis.
      ). The authors point out that the protocol still does not totally eliminate the risk of acute fetal death before onset of labor.
      To date no randomized trials have been conducted to investigate the optimal surveillance level at a costbenefit basis. Most authors agree that weekly CTG registrations are valuable, at least from the 34th week of gestation on. Weekly assessments of serum bile acids, transaminases, and bilirubin should be conducted. In severe cases or if the patient suffers from steatorrhea, control of prothrombin time should be considered. Obstetric management consists of weighing the risk of premature delivery against the risk of sudden death in utero. In addition, it has to be considered that induction of labor is associated with a higher frequency of complications such as operative deliveries compared to spontaneous labor. Since fetal prognosis correlates with disease severity (
      • Laatikainen T
      • Tulenheimo A
      Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy.
      ,
      • Laatikainen T
      • Ikonen E
      Fetal prognosis in obstetric hepatosis.
      ,
      • Reid R
      • Ivey KJ
      • Rencoret RH
      • Storey B
      Fetal complications of obstetric cholestasis.
      ), the aim of treatment should be reduction of bile acids in order to prolong the pregnancy and reduce both fetal risk and maternal symptoms.
      Frequencies of abortions and malformations are not increased in ICP. Birthweights are adequate for gestational age. Breastfeeding is not contraindicated. Patients with a history of ICP may use low-dose oral contraceptives after normalization of liver function tests, provided they are instructed to stop medication if pruritus and cholestasis recur.

      Pharmacological Treatment

      Antihistamines, anion exchange resins and phenobarbital are given to remove putative peripheral pruritogens or to reverse their effects on empiric grounds (
      • Jones EA
      • Bergasa NV
      The pruritus of cholestasis.
      ). These therapeutic options have not received wide acceptance for treatment of ICP patients because of their ambiguous efficacy or side effects. Anion exchange resins such as colestipol or colestyramine bind bile acids and interrupt their enterohepatic circulation. They should therefore be given separately from ursodeoxycholic acid (UDCA, see below) (
      • Rust C
      • Sauter GH
      • Oswald M
      • Buttner J
      • Kullak-Ublick GA
      • Paumgartner G
      • et al.
      Effect of cholestyramine on bile acid pattern and synthesis during administration of ursodeoxycholic acid in man.
      ). Since both ICP and colestyramine may independently lead to vitamin K deficiency, it is important that ICP patients who are treated with anion resins receive parenteral substitution of fat-soluble vitamins (A, D, and K). Because of the risks of antepartal fetal hemorrhage (
      • Sadler LC
      • Lane M
      • North R
      Severe fetal intracranial haemorrhage during treatment with cholestyramine for intrahepatic cholestasis of pregnancy.
      ) and intra- and postpartal maternal bleedings, and the minor effect on pruritus, colestyramine is nowadays not considered first-line therapy for ICP.
      S-adenosylmethionine (SAM) improves cholestasis in the ethinylestradiol-treated rat (
      • Boelsterli UA
      • Rakhit G
      • Balazs T
      Modulation by S-adenosyl-L-methionine of hepatic Na+,K+-ATPase, membrane fluidity, and bile flow in rats with ethinyl estradiol-induced cholestasis.
      ). It is a precursor of glutathione and, as a universal methyl group donor, involved in the hepatic synthesis of phosphatidylcholine. Thus, SAM has been proposed to influence not only the composition and fluidity of hepatocyte plasma membranes, but also methylation and biliary excretion of hormone metabolites. In two Italian ICP studies, daily intravenous application of 800 mg SAM for 20 days (
      • Frezza M
      • Pozzato G
      • Chiesa L
      • Stramentinoli G
      • di Padova C
      Reversal of intrahepatic cholestasis of pregnancy in women after high dose S-adenosyl-L-methionine administration.
      ) or oral application of 1600 mg SAM (
      • Frezza M
      • Surrenti C
      • Manzillo G
      • Fiaccadori F
      • Bortolini M
      • Di Padova C
      Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebocontrolled study.
      ) resulted in significant decreases of pruritus, bilirubin, and ALT. However, 900 mg SAM in daily intravenous infusions were without effect in a double-blind, placebo-controlled study in 9 Chilean patients with moderate or severe ICP (
      • Ribalta J
      • Reyes H
      • Gonzalez MC
      • Iglesias J
      • Arrese M
      • Poniachik J
      • et al.
      S-adenosyl-L-methionine in the treatment of patients with intrahepatic cholestasis of pregnancy: a randomized, double-blind, placebo-controlled study with negative results.
      ). In conclusion, the role of SAM in ICP treatment is still a matter of debate.
      Phenobarbital was once thought to be a therapeutic alternative for ICP, but it relieved pruritus in only 50% of the patients and showed no beneficial effects on liver parameters (
      • Laatikainen T
      Effect of cholestyramine and phenobarbital on pruritus and serum bile acid levels in cholestasis of pregnancy.
      ,
      • Heikkinen J
      • Maentausta O
      • Ylostalo P
      • Janne O
      Serum bile acid levels in intrahepatic cholestasis of pregnancy during treatment with phenobarbital or cholestyramine.
      ). Dexamethasone and UDCA are treatment options being currently evaluated. Dexamethasone inhibits the feto-placental hormone synthesis, and a single study demonstrated significant improvement of pruritus, bile acids and ALT in 10 patients, who were treated with dexamethasone at an initial dose of 12 mg four times daily for 7 days with subsequent dose tapering over 3 days (
      • Hirvioja ML
      • Tuimala R
      • Vuori J
      The treatment of intrahepatic cholestasis of pregnancy by dexamethasone.
      ).
      UDCA, a naturally occurring hydrophilic bile acid (
      • Hagey LR
      • Crombie DL
      • Espinosa E
      • Carey MC
      • Igimi H
      • Hofmann AF
      Ursodeoxycholic acid in the Ursidae: biliary bile acids of bears, pandas, and related carnivores.
      ), improves clinical and biochemical indices in a variety of cholestatic liver diseases (
      • Beuers U
      • Boyer JL
      • Paumgartner G
      Ursodeoxycholic acid in cholestasis: potential mechanisms of action and therapeutic applications.
      ). It is nowadays considered as the first-line treatment option for patients with primary biliary cirrhosis (PBC), because the results from the combined analysis of the three largest randomized clinical trials of UDCA in PBC indicate that UDCA improves survival free of liver transplantation (
      • Poupon RE
      • Lindor KD
      • Cauch-Dudek K
      • Dickson ER
      • Poupon R
      • Heathcote EJ
      Combined analysis of randomized controlled trials of ursodeoxycholic acid in primary biliary cirrhosis.
      ). These results are under intense discussion (
      • Goulis J
      • Leandro G
      • Burroughs AK
      Randomised controlled trials of ursodeoxycholic-acid therapy for primary biliary cirrhosis: a meta-analysis.
      ,
      • Neuberger J
      Urso - panacea or placebo?.
      ,
      • Poupon RE
      Ursodeoxycholic acid for primary biliary cirrhosis: lessons from the past - issues for the future.
      ). The mechanisms of action of UDCA are still under debate. There is evidence that the hydrophilic UDCA protects against injury to bile ducts by hydrophobic bile acids and stimulates the excretion of these and other potentially hepatotoxic compounds (
      • Beuers U
      • Boyer JL
      • Paumgartner G
      Ursodeoxycholic acid in cholestasis: potential mechanisms of action and therapeutic applications.
      ).
      Based on the positive experiences in PBC, UDCA has been used for the treatment for ICP as well. In a study with 20 ICP patients, UDCA at a dose of 450 mg/day was more effective in relieving itching and lowering serum bile acids than SAM at a dose of 1000 mg/day (
      • Floreani A
      • Paternoster D
      • Melis A
      • Grella PV
      S-adenosylmethionine versus ursodeoxycholic acid in the treatment of intrahepatic cholestasis of pregnancy: preliminary results of a controlled trial.
      ). The beneficial effects of UDCA have been confirmed in two small randomized double-blind placebo-controlled trials in 16 patients with ICP (
      • Diaferia A
      • Nicastri PL
      • Tartagni M
      • Loizzi P
      • Iacovizzi C
      • Di Leo A
      Ursodeoxycholic acid therapy in pregnant women with cholestasis.
      ,
      • Palma J
      • Reyes H
      • Ribalta J
      • Hernandez I
      • Sandoval L
      • Almuna R
      • et al.
      Ursodeoxycholic acid in the treatment of cholestasis of pregnancy: a randomized, double-blind study controlled with placebo.
      ). At a dose of 600–1000 mg per day, significant improvements in pruritus, bilirubin and transaminases were observed.
      In ICP patients, UDCA normalizes the increased CA/CDCA ratio (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Effects of ursodeoxycholic acid on conjugated bile acids and progesterone metabolites in serum and urine of patients with intrahepatic cholestasis of pregnancy.
      ,
      • Brites D
      • Rodrigues CM
      • Oliveira N
      • Cardoso M
      • Graca LM
      Correction of maternal serum bile acid profile during ursodeoxycholic acid therapy in cholestasis of pregnancy.
      ) and reduces plasma concentrations as well as urinary excretion rates of sulfated steroid metabolites (
      • Meng LJ
      • Reyes H
      • Palma J
      • Hernandez I
      • Ribalta J
      • Sjövall J
      Effects of ursodeoxycholic acid on conjugated bile acids and progesterone metabolites in serum and urine of patients with intrahepatic cholestasis of pregnancy.
      ). Furthermore, administration of UDCA both restores the impaired bile acid transport across the trophoblast in ICP (
      • Serrano MA
      • Brites D
      • Larena MG
      • Monte MJ
      • Bravo MP
      • Oliveira N
      • et al.
      Beneficial effect of ursodeoxycholic acid on alterations induced by cholestasis of pregnancy in bile acid transport across the human placenta.
      ) and decreases the delivery of bile acids to the fetus (
      • Brites D
      • Rodrigues CM
      • Cardoso M da C
      • Graca LM
      Unusual case of severe cholestasis of pregnancy with early onset, improved by ursodeoxycholic acid administration.
      ,
      • Brites D
      • Rodrigues CM
      • Oliveira N
      • Cardoso M
      • Graca LM
      Correction of maternal serum bile acid profile during ursodeoxycholic acid therapy in cholestasis of pregnancy.
      ,
      • Brites D
      • Rodrigues CM
      Elevated levels of bile acids in colostrum of patients with cholestasis of pregnancy are decreased following ursodeoxycholic acid therapy.
      ,
      • Davies MH
      • da Silva RC
      • Jones SR
      • Weaver JB
      • Elias E
      Fetal mortality associated with cholestasis of pregnancy and the potential benefit of therapy with ursodeoxycholic acid.
      ,
      • Floreani A
      • Paternoster D
      • Grella V
      • Sacco S
      • Gangemi M
      • Chiaramonte M
      Ursodeoxycholic acid in intrahepatic cholestasis of pregnancy.
      ,
      • Palma J
      • Reyes H
      • Ribalta J
      • Iglesias J
      • Gonzalez MC
      • Hernandez I
      • Alvarez C
      • et al.
      Effects of ursodeoxycholic acid in patients with intrahepatic cholestasis of pregnancy.
      ,
      • Mazzella G
      • Rizzo N
      • Salzetta A
      • Iampieri R
      • Bovicelli L
      • Roda E
      Management of intrahepatic cholestasis in pregnancy.
      ), representing a valuable contribution to fetal well-being and outcome (
      • Palma J
      • Reyes H
      • Ribalta J
      • Hernandez I
      • Sandoval L
      • Almuna R
      • et al.
      Ursodeoxycholic acid in the treatment of cholestasis of pregnancy: a randomized, double-blind study controlled with placebo.
      ).
      UDCA has virtually no side-effects except for mild diarrhea in rare cases. Up to now, no adverse effects on the fetus have been reported. Because the start of treatment with UDCA is usually delayed until the third trimester, the risk of teratogenicity is further minimized. Because UDCA has not yet been approved for ICP treatment, results of future larger randomized, controlled UDCA trials in ICP patients are eagerly awaited.

      References

        • Ahlfeld F
        Berichte und Arbeiten aus der Geburtshilflich-Gynäkologischen Klinik zu Gießen 1881-1882.
        Grunow, Leipzig1883
        • Kreek MJ
        Female sex steroids and cholestasis.
        Semin Liver Dis. 1987; 7: 8-23
        • Bacq Y
        • Sapey T
        • Brechot MC
        • Pierre F
        • Fignon A
        • Dubois F
        Intrahepatic cholestasis of pregnancy: a French prospective study.
        Hepatology. 1997; 26: 358-364
        • Fisk NM
        • Storey GN
        Fetal outcome in obstetric cholestasis.
        Br J Obstet Gynaecol. 1988; 95: 1137-1143
        • Rioseco AJ
        • Ivankovic MB
        • Manzur A
        • Hamed F
        • Kato SR
        • Parer JT
        • et al.
        Intrahepatic cholestasis of pregnancy: a retrospective case-control study of perinatal outcome.
        Am J Obstet Gynecol. 1994; 170: 890-895
        • Shaw D
        • Frohlich J
        • Wittmann BA
        • Willms M
        A prospective study of 18 patients with cholestasis of pregnancy.
        Am J Obstet Gynecol. 1982; 142: 621-625
        • Fisk NM
        • Bye WB
        • Storey GN
        Maternal features of obstetric cholestasis: 20 years experience at King George V Hospital.
        Aust N Z J Obstet Gynaecol. 1988; 28: 172-176
        • Alsulyman OM
        • Ouzounian JG
        • Ames-Castro M
        • Goodwin TM
        Intrahepatic cholestasis of pregnancy: perinatal outcome associated with expectant management.
        Am J Obstet Gynecol. 1996; 175: 957-960
        • Berg B
        • Helm G
        • Petersohn L
        • Tryding N
        Cholestasis of pregnancy. Clinical and laboratory studies.
        Acta Obstet Gynecol Scand. 1986; 65: 107-113
        • Laatikainen T
        • Tulenheimo A
        Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy.
        Int J Gynaecol Obstet. 1984; 22: 91-94
        • Forker EL
        The effect of estrogen on bile formation in the rat.
        J Clin Invest. 1969; 48: 654-663
        • Davis RA
        • Kern Jr., F
        • Showalter R
        • Sutherland E
        • Sinensky M
        • Simon FR
        Alterations of hepatic Na+,K+-ATPase and bile flow by estrogen: effects on liver surface membrane lipid structure and function.
        Proc Natl Acad Sci USA. 1978; 75: 4130-4134
        • Simon FR
        The role of sex hormones and hepatic plasma membranes in the pathogenesis of cholestasis.
        in: Reyes HB Leuschner U Arias IM Pregnancy, Sex Hormones and the Liver. Kluwer, Dordrecht1996: 51-58
        • Boelsterli UA
        • Rakhit G
        • Balazs T
        Modulation by S-adenosyl-L-methionine of hepatic Na+,K+-ATPase, membrane fluidity, and bile flow in rats with ethinyl estradiol-induced cholestasis.
        Hepatology. 1983; 3: 12-17
        • Simon FR
        • Fortune J
        • Iwahashi M
        • Gartung C
        • Wolkoff A
        • Sutherland E
        Ethinyl estradiol cholestasis involves alterations in expression of liver sinusoidal transporters.
        Am J Physiol. 1996; 271: G1043-G1052
        • Stieger B
        • Fattinger K
        • Madon J
        • Kullak-Ublick GA
        • Meier PJ
        Drug- and estrogen-induced cholestasis through inhibition of the hepatocellular bile salt export pump (Bsep) of rat liver.
        Gastroenterology. 2000; 118: 422-430
        • Trauner M
        • Arrese M
        • Soroka CJ
        • Ananthanarayanan M
        • Koeppel TA
        • Schlosser SF
        • et al.
        The rat canalicular conjugate export pump (Mrp2) is down-regulated in intrahepatic and obstructive cholestasis.
        Gastroenterology. 1997; 113: 255-264
        • Meyers M
        • Slikker W
        • Vore M
        Steroid D-ring glucuronides: characterization of a new class of cholestatic agents in the rat.
        J Pharmacol Exp Ther. 1981; 218: 63-73
        • Adlercreutz H
        • Tikkanen MJ
        • Wichmann K
        • Svanborg A
        • Anberg A
        Recurrent jaundice in pregnancy. IV. Quantitative determination of urinary and biliary estrogens, including studies in pruritus gravidarum.
        J Clin Endocrinol Metab. 1974; 38: 51-57
        • Vore M
        Estrogen cholestasis. Membranes, metabolites, or receptors?.
        Gastroenterology. 1987; 93: 643-649
        • Davies MH
        • Ngong JM
        • Yucesoy M
        • Acharya SK
        • Mills CO
        • Weaver JB
        • et al.
        The adverse influence of pregnancy upon sulphation: a clue to the pathogenesis of intrahepatic cholestasis of pregnancy?.
        J Hepatol. 1994; 21: 1127-1134
        • Sjövall J
        • Reyes H
        Bile acids and progesterone metabolites in intrahepatic cholestasis of pregnancy.
        Ann Med. 2000; 32: 94-106
        • Lutz EE
        • Margolis AJ
        Obstetric hepatosis: treatment with cholestyramine and interim response to steroids.
        Obstet Gynecol. 1969; 33: 64-71
        • Bacq Y
        Intrahepatic cholestasis of pregnancy.
        Clinics Liver Dis. 1999; 3: 1-13
        • Sjövall J
        • Sjövall K
        Steroid sulphates in plasma from pregnant women with pruritus and elevated plasma bile acid levels.
        Ann Clin Res. 1970; 2: 321-337
        • Laatikainen TJ
        • Peltonen JI
        • Nylander PL
        Effect of maternal intrahepatic cholestasis on fetal steroid metabolism.
        J Clin Invest. 1974; 53: 1709-1715
        • Giusti G
        • Piccinino F
        • Ricciardi I
        • Delrio G
        • Sagnelli E
        • Manzillo G
        Abnormal steroid sulfate in plasma of women with intrahepatic cholestasis of pregnancy.
        Acta Hepatogastroenterol. 1979; 26: 203-206
        • Sjövall K
        Gas chromatographic determination of steroid sulphates in plasma during pregnancy.
        Ann Clin Res. 1970; 2: 393-408
        • Meng LJ
        • Reyes H
        • Axelson M
        • Palma J
        • Hernandez I
        • Ribalta J
        • et al.
        Progesterone metabolites and bile acids in serum of patients with intrahepatic cholestasis of pregnancy: effect of ursodeoxycholic acid therapy.
        Hepatology. 1997; 26: 1573-1579
        • Meng LJ
        • Reyes H
        • Palma J
        • Hernandez I
        • Ribalta J
        • Sjövall J
        Profiles of bile acids and progesterone metabolites in the urine and serum of women with intrahepatic cholestasis of pregnancy.
        J Hepatol. 1997; 27: 346-357
        • Laatikainen T
        • Karjalainen O
        Exertion of progesterone metabolites in urine and bile of pregnant women with intrahepatic cholestasis.
        J Steroid Biochem. 1973; 4: 641-648
        • Eriksson H
        • Gustafsson JA
        • Sjövall J
        • Sjövall K
        Excretion of neutral steroids in urine and faeces of women with intrahepatic cholestasis of pregnancy.
        Steroids Lipids Res. 1972; 3: 30-48
        • Meng LJ
        • Griffiths WJ
        • Sjövall J
        The identification of novel steroid N-acetylglucosaminides in the urine of pregnant women.
        J Steroid Biochem Mol Biol. 1996; 58: 585-598
        • Marschall HU
        • Matern H
        • Wietholtz H
        • Egestad B
        • Matern S
        • Sjovall J
        Bile acid N-acetylglucosaminidation. In vivo and in vitro evidence for a selective conjugation reaction of 7 beta-hydroxylated bile acids in humans.
        J Clin Invest. 1992; 89: 1981-1987
        • Marschall HU
        • Griffiths WJ
        • Gotze U
        • Zhang J
        • Wietholtz H
        • Busch N
        • et al.
        The major metabolites of ursodeoxycholic acid in human urine are conjugated with N-acetylglucosamine.
        Hepatology. 1994; 20: 845-853
        • Lindblad A
        • Glaumann H
        • Strandvik B
        A two-year prospective study of the effect of ursodeoxycholic acid on urinary bile acid excretion and liver morphology in cystic fibrosis-associated liver disease.
        Hepatology. 1998; 27: 166-174
        • Reyes H
        • Gonzalez MC
        • Ribalta J
        • Aburto H
        • Matus C
        • Schramm G
        • et al.
        Prevalence of intrahepatic cholestasis of pregnancy in Chile.
        Ann Intern Med. 1978; 88: 487-493
        • Holzbach RT
        • Sivak DA
        • Braun WE
        Familial recurrent intrahepatic cholestasis of pregnancy: a genetic study providing evidence for transmission of a sex-limited, dominant trait.
        Gastroenterology. 1983; 85: 175-179
        • Reyes H
        • Ribalta J
        • Gonzalez-Ceron M
        Idiopathic cholestasis of pregnancy in a large kindred.
        Gut. 1976; 17: 709-713
        • Dalen E
        • Westerholm B
        Occurrence of hepatic impairment in women jaundiced by oral contraceptives and in their mothers and sisters.
        Acta Med Scand. 1974; 195: 459-463
        • Furhoff AK
        Itching in pregnancy. A 15-year follow-up study.
        Acta Med Scand. 1974; 196: 403-410
        • Hirvioja ML
        • Kivinen S
        Inheritance of intrahepatic cholestasis of pregnancy in one kindred.
        Clin Genet. 1993; 43: 315-317
        • Trauner M
        • Meier PJ
        • Boyer JL
        Molecular pathogenesis of cholestasis.
        N Engl J Med. 1998; 339: 1217-1227
        • Oude Elferink RP
        • van Berge Henegouwen GP
        Cracking the genetic code for benign recurrent and progressive familial intrahepatic cholestasis.
        J Hepatol. 1998; 29: 317-320
        • Jansen PLM
        • Muller M
        The molecular genetics of familial intrahepatic cholestasis.
        Gut. 2000; 47: 1-5
        • Bull LN
        • van Eijk MJ
        • Pawlikowska L
        • DeYoung JA
        • Juijn JA
        • Liao M
        • et al.
        A gene encoding a P-type ATPase mutated in two forms of hereditary cholestasis.
        Nature Genet. 1998; 18: 219-224
        • Strautnieks SS
        • Bull LN
        • Knisely AS
        • Kocoshis SA
        • Dahl N
        • Arnell H
        • et al.
        A gene encoding a liver-specific ABC transporter is mutated in progressive familial intrahepatic cholestasis.
        Nature Genet. 1998; 20: 233-238
        • De Vree JM
        • Jacquemin E
        • Sturm E
        • Cresteil D
        • Bosma PJ
        • Aten J
        • et al.
        Mutations in the MDR3 gene cause progressive familial intrahepatic cholestasis.
        Proc Natl Acad Sci USA. 1998; 95: 282-287
        • De Pagter AG
        • van Berge Henegouwen GP
        • ten Bokkel Huinink JA
        • Brandt KH
        Familial benign recurrent intrahepatic cholestasis. Interrelation with intrahepatic cholestasis of pregnancy and from oral contraceptives?.
        Gastroenterology. 1976; 71: 202-207
        • Clayton RJ
        • Iber FL
        • Ruebner BH
        • McKusick VA
        Byler disease. Fatal familial intrahepatic cholestasis in an Amish kindred.
        Am J Dis Child. 1969; 117: 112-124
        • Whitington PF
        • Freese DK
        • Alonso EM
        • Schwarzenberg SJ
        • Sharp HL
        Clinical and biochemical findings in progressive familial intrahepatic cholestasis.
        J Pediatr Gastroenterol Nutr. 1994; 18: 134-141
        • Jacquemin E
        • Cresteil D
        • Manouvrier S
        • Boute O
        • Hadchouel M
        Heterozygous non-sense mutation of the MDR3 gene in familial intrahepatic cholestasis of pregnancy.
        Lancet. 1999; 353: 210-211
        • Dixon PH
        • Weerasekera N
        • Linton KJ
        • Donaldson O
        • Chambers J
        • Egginton E
        • et al.
        Heterozygous MDR3 missense mutation associated with intrahepatic cholestasis of pregnancy: evidence for a defect in protein trafficking.
        Hum Mol Genet. 2000; 9: 1209-1217
        • Debry P
        • Nash EA
        • Neklason DW
        • Metherall JE
        Role of multidrug resistance P-glycoproteins in cholesterol esterification.
        J Biol Chem. 1997; 272: 1026-1031
        • Laatikainen T
        • Ikonen E
        Fetal prognosis in obstetric hepatosis.
        Ann Chir Gynaecol Fenn. 1975; 64: 155-164
        • Humberto R
        • Báez ME
        • González MC
        • Hernández I
        • Palma J
        • Ribalta J
        • et al.
        Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals in Chile.
        J Hepatol. 2000; 32: 542-549
        • Kauppila A
        • Korpela H
        • Makila UM
        • Yrjanheikki E
        Low serum selenium concentration and glutathione peroxidase activity in intrahepatic cholestasis of pregnancy.
        Br Med J (Clin Res Ed). 1987; 294: 150-152
        • Reid R
        • Ivey KJ
        • Rencoret RH
        • Storey B
        Fetal complications of obstetric cholestasis.
        Br Med J. 1976; 1: 870-872
        • Zimmermann P
        • Koskinen J
        • Vaalamo P
        • Ranta T
        Doppler umbilical artery velocimetry in pregnancies complicated by intrahepatic cholestasis.
        J Perinat Med. 1991; 19: 351-355
        • Campos GA
        • Guerra FA
        • Israel EJ
        Effects of cholic acid infusion in fetal lambs.
        Acta Obstet Gynecol Scand. 1986; 65: 23-26
        • Altshuler G
        • Hyde S
        Meconium-induced vasocontraction: a potential cause of cerebral and other fetal hypoperfusion and of poor pregnancy outcome.
        J Child Neurol. 1989; 4: 137-142
        • Altshuler G
        • Arizawa M
        • Molnar-Nadasdy G
        Meconium-induced umbilical cord vascular necrosis and ulceration: a potential link between the placenta and poor pregnancy outcome.
        Obstet Gynecol. 1992; 79: 760-766
        • Brites D
        • Rodrigues CM
        • Cardoso M da C
        • Graca LM
        Unusual case of severe cholestasis of pregnancy with early onset, improved by ursodeoxycholic acid administration.
        Eur J Obstet Gynecol Reprod Biol. 1998; 76: 165-168
        • Heikkinen J
        • Maentausta O
        • Tuimala R
        • Ylostalo P
        • Janne O
        Amniotic fluid bile acids in normal and pathologic pregnancy.
        Obstet Gynecol. 1980; 56: 60-64
        • Laatikainen TJ
        Fetal bile acid levels in pregnancies complicated by maternal intrahepatic cholestasis.
        Am J Obstet Gynecol. 1975; 122: 852-856
        • Rodrigues CM
        • Marin JJ
        • Brites D
        Bile acid patterns in meconium are influenced by cholestasis of pregnancy and not altered by ursodeoxycholic acid treatment.
        Gut. 1999; 45: 446-452
        • Sepulveda WH
        • Gonzalez C
        • Cruz MA
        • Rudolph MI
        Vasoconstrictive effect of bile acids on isolated human placental chorionic veins.
        Eur J Obstet Gynecol Reprod Biol. 1991; 42: 211-215
        • Serrano MA
        • Brites D
        • Larena MG
        • Monte MJ
        • Bravo MP
        • Oliveira N
        • et al.
        Beneficial effect of ursodeoxycholic acid on alterations induced by cholestasis of pregnancy in bile acid transport across the human placenta.
        J Hepatol. 1998; 28: 829-839
        • Macias RI
        • Pascual MJ
        • Bravo A
        • Alcalde MP
        • Larena MG
        • St - Pierre MV
        • et al.
        Effect of maternal cholestasis on bile acid transfer across the rat placenta-maternal liver tandem.
        Hepatology. 2000; 31: 975-983
        • Huchzermeyer H
        Leber und Schwangerschaft.
        Huber, Bern1978
        • Olsson R
        • Tysk C
        • Aldenborg F
        • Holm B
        Prolonged postpartum course of intrahepatic cholestasis of pregnancy.
        Gastroenterology. 1993; 105: 267-271
        • Leevy CB
        • Koneru B
        • Klein KM
        Recurrent familial prolonged intrahepatic cholestasis of pregnancy associated with chronic liver disease.
        Gastroenterology. 1997; 113: 966-972
        • Samsioe G
        • Svendsen P
        • Johnson P
        • Gustafson A
        Studies in cholestasis of pregnancy. V. Gallbladder disease, liver function tests, serum lipids and fatty acid composition of serum lecithin in the non-pregnant state.
        Acta Obstet Gynecol Scand. 1975; 54: 417-423
        • Glasinovic JC
        • Valdivieso V
        • Covarrubias C
        • Marinovic I
        • Miquel JF
        • Nervo F
        Pregnancy and gallstones.
        in: Reyes HB Leuschner U Arias IM Pregnancy, Sex Hormones and the Liver. Kluwer, Dordrecht1996: 267-281
        • Furhoff AK
        • Hellstrom K
        Jaundice in pregnancy. A follow-up study of the series of women originally reported by L. Thorling. II. Present health of the women.
        Acta Med Scand. 1974; 196: 181-189
        • Kirkinen P
        • Ylostalo P
        • Heikkinen J
        • Maentausta O
        Gallbladder function and maternal bile acids in intrahepatic cholestasis of pregnancy.
        Eur J Obstet Gynecol Reprod Biol. 1984; 18: 29-34
        • Ylöstalo P
        • Kirkinen P
        • Heikkinen J
        • Maentausta O
        • Jarvinen PA
        Gall bladder volume and serum bile acids in cholestasis of pregnancy.
        Br J Obstet Gynaecol. 1982; 89: 59-61
        • Apstein MD
        • Carey MC
        Pathogenesis of cholesterol gallstones: a parsimonious hypothesis.
        Eur J Clin Invest. 1996; 26: 343-352
        • Lammert F
        • Carey MC
        • Paigen B
        Chromosomal organization of candidate genes involved in cholesterol gallstone formation: a murine 'gallstone map'.
        Gastroenterology. 2000; 119 (in press)
        • Pratt DS
        • Kaplan MM
        Evaluation of abnormal liver-enzyme results in asymptomatic patients.
        N Engl J Med. 2000; 342: 1266-1271
        • Jeppsson S
        • Laurell CB
        • Rannevik G
        Plasma proteins after use of estrogen and-or progestogen in women with and without recurrent cholestasis during previous pregnancies.
        Scand J Clin Lab Invest. 1973; 31: 33-36
        • Lunzer M
        • Barnes P
        • Byth K
        • O'Halloran M
        Serum bile acid concentrations during pregnancy and their relationship to obstetric cholestasis.
        Gastroenterology. 1986; 91: 825-829
        • Laatikainen T
        • Hesso A
        Determination of serum bile acids by glass capillary gas-liquid chromatography.
        Clin Chim Acta. 1975; 64: 63-68
        • Laatikainen T
        • Ikonen E
        Serum bile acids in cholestasis of pregnancy.
        Obstet Gynecol. 1977; 50: 313-318
        • Brites D
        • Rodrigues CM
        • Oliveira N
        • Cardoso M
        • Graca LM
        Correction of maternal serum bile acid profile during ursodeoxy-cholic acid therapy in cholestasis of pregnancy.
        J Hepatol. 1998; 28: 91-98
        • Carter J
        Serum bile acids in normal pregnancy.
        Br J Obstet Gynecol. 1991; 98: 540-543
        • Sjövall K
        • Sjövall J
        Serum bile acid levels in pregnancy with pruritus (bile acids and steroids 158).
        Clin Chim Acta. 1966; 13: 207-211
        • Bacq Y
        • Myara A
        • Brechot MC
        • Hamon C
        • Studer E
        • Trivin F
        • et al.
        Serum conjugated bile acid profile during intrahepatic cholestasis of pregnancy.
        J Hepatol. 1995; 22: 66-70
        • Heikkinen J
        Serum bile acids in the early diagnosis of intrahepatic cholestasis of pregnancy.
        Obstet Gynecol. 1983; 61: 581-587
        • Laatikainen T
        • Lehtonen P
        • Hesso A
        Biliary bile acids in uncomplicated pregnancy and in cholestasis of pregnancy.
        Clin Chem Acta. 1978; 85: 145-150
        • Wolf JL
        Liver disease in pregnancy.
        Med Clin North Am. 1996; 80: 1167-1187
        • Forkman B
        • Ganrot PO
        • Gennser G
        • Rannevik G
        Plasma protein pattern in recurrent cholestasis of pregnancy.
        Scand J Clin Lab Invest Suppl. 1972; 124: 89-96
        • Oude Elferink RP
        • Ottenhoff R
        • van Marle J
        • Frijters CM
        • Smith AJ
        • Groen AK
        Class III P-glycoproteins mediate the formation of lipoprotein X in the mouse.
        J Clin Invest. 1998; 102: 1749-1757
        • Adlercreutz H
        • Svanborg A
        • Anberg A
        Recurrent jaundice in pregnancy. I. A clinical and ultrastructural study.
        Am J Med. 1967; 42: 335-340
        • Schmid R
        • Haemmerli UP
        Der Schwangerschaftsikterus.
        in: Beck K Ikterus. Schattauer, Stuttgart1968: 227-231
        • Reyes H
        • Simon FR
        Intrahepatic cholestasis of pregnancy: an estrogen-related disease.
        Semin Liver Dis. 1993; 13: 289-301
        • Jones EA
        • Bergasa NV
        The pruritus of cholestasis.
        Hepatology. 1999; 29: 1003-1006
        • Rust C
        • Sauter GH
        • Oswald M
        • Buttner J
        • Kullak-Ublick GA
        • Paumgartner G
        • et al.
        Effect of cholestyramine on bile acid pattern and synthesis during administration of ursodeoxycholic acid in man.
        Eur J Clin Invest. 2000; 30: 135-139
        • Sadler LC
        • Lane M
        • North R
        Severe fetal intracranial haemorrhage during treatment with cholestyramine for intrahepatic cholestasis of pregnancy.
        Br J Obstet Gynaecol. 1995; 102: 169-170
        • Frezza M
        • Pozzato G
        • Chiesa L
        • Stramentinoli G
        • di Padova C
        Reversal of intrahepatic cholestasis of pregnancy in women after high dose S-adenosyl-L-methionine administration.
        Hepatology. 1984; 4: 274-278
        • Frezza M
        • Surrenti C
        • Manzillo G
        • Fiaccadori F
        • Bortolini M
        • Di Padova C
        Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis. A double-blind, placebocontrolled study.
        Gastroenterology. 1990; 99: 211-215
        • Ribalta J
        • Reyes H
        • Gonzalez MC
        • Iglesias J
        • Arrese M
        • Poniachik J
        • et al.
        S-adenosyl-L-methionine in the treatment of patients with intrahepatic cholestasis of pregnancy: a randomized, double-blind, placebo-controlled study with negative results.
        Hepatology. 1991; 13: 1084-1089
        • Laatikainen T
        Effect of cholestyramine and phenobarbital on pruritus and serum bile acid levels in cholestasis of pregnancy.
        Am J Obstet Gynecol. 1978; 132: 501-506
        • Heikkinen J
        • Maentausta O
        • Ylostalo P
        • Janne O
        Serum bile acid levels in intrahepatic cholestasis of pregnancy during treatment with phenobarbital or cholestyramine.
        Eur J Obstet Gynecol Reprod Biol. 1982; 14: 153-162
        • Hirvioja ML
        • Tuimala R
        • Vuori J
        The treatment of intrahepatic cholestasis of pregnancy by dexamethasone.
        Br J Obstet Gynaecol. 1992; 99: 109-111
        • Hagey LR
        • Crombie DL
        • Espinosa E
        • Carey MC
        • Igimi H
        • Hofmann AF
        Ursodeoxycholic acid in the Ursidae: biliary bile acids of bears, pandas, and related carnivores.
        J Lipid Res. 1993; 34: 1911-1917
        • Beuers U
        • Boyer JL
        • Paumgartner G
        Ursodeoxycholic acid in cholestasis: potential mechanisms of action and therapeutic applications.
        Hepatology. 1998; 28: 1449-1453
        • Poupon RE
        • Lindor KD
        • Cauch-Dudek K
        • Dickson ER
        • Poupon R
        • Heathcote EJ
        Combined analysis of randomized controlled trials of ursodeoxycholic acid in primary biliary cirrhosis.
        Gastroenterology. 1997; 113: 884-890
        • Goulis J
        • Leandro G
        • Burroughs AK
        Randomised controlled trials of ursodeoxycholic-acid therapy for primary biliary cirrhosis: a meta-analysis.
        Lancet. 1999; 354: 1053-1060
        • Neuberger J
        Urso - panacea or placebo?.
        Hepatology. 2000; 31: 1027-1028
        • Poupon RE
        Ursodeoxycholic acid for primary biliary cirrhosis: lessons from the past - issues for the future.
        J Hepatol. 2000; 32: 685-688
        • Floreani A
        • Paternoster D
        • Melis A
        • Grella PV
        S-adenosylmethionine versus ursodeoxycholic acid in the treatment of intrahepatic cholestasis of pregnancy: preliminary results of a controlled trial.
        Eur J Obstet Gynecol Reprod Biol. 1996; 67: 109-113
        • Diaferia A
        • Nicastri PL
        • Tartagni M
        • Loizzi P
        • Iacovizzi C
        • Di Leo A
        Ursodeoxycholic acid therapy in pregnant women with cholestasis.
        Int J Gynaecol Obstet. 1996; 52: 133-140
        • Palma J
        • Reyes H
        • Ribalta J
        • Hernandez I
        • Sandoval L
        • Almuna R
        • et al.
        Ursodeoxycholic acid in the treatment of cholestasis of pregnancy: a randomized, double-blind study controlled with placebo.
        J Hepatol. 1997; 27: 1022-1028
        • Meng LJ
        • Reyes H
        • Palma J
        • Hernandez I
        • Ribalta J
        • Sjövall J
        Effects of ursodeoxycholic acid on conjugated bile acids and progesterone metabolites in serum and urine of patients with intrahepatic cholestasis of pregnancy.
        J Hepatol. 1997; 27: 1029-1040
        • Brites D
        • Rodrigues CM
        • Oliveira N
        • Cardoso M
        • Graca LM
        Correction of maternal serum bile acid profile during ursodeoxycholic acid therapy in cholestasis of pregnancy.
        J Hepatol. 1998; 28: 91-98
        • Brites D
        • Rodrigues CM
        Elevated levels of bile acids in colostrum of patients with cholestasis of pregnancy are decreased following ursodeoxycholic acid therapy.
        J Hepatol. 1998; 29: 743-751
        • Davies MH
        • da Silva RC
        • Jones SR
        • Weaver JB
        • Elias E
        Fetal mortality associated with cholestasis of pregnancy and the potential benefit of therapy with ursodeoxycholic acid.
        Gut. 1995; 37: 580-584
        • Floreani A
        • Paternoster D
        • Grella V
        • Sacco S
        • Gangemi M
        • Chiaramonte M
        Ursodeoxycholic acid in intrahepatic cholestasis of pregnancy.
        Br J Obstet Gynaecol. 1994; 101: 64-65
        • Palma J
        • Reyes H
        • Ribalta J
        • Iglesias J
        • Gonzalez MC
        • Hernandez I
        • Alvarez C
        • et al.
        Effects of ursodeoxycholic acid in patients with intrahepatic cholestasis of pregnancy.
        Hepatology. 1992; 15: 1043-1047
        • Mazzella G
        • Rizzo N
        • Salzetta A
        • Iampieri R
        • Bovicelli L
        • Roda E
        Management of intrahepatic cholestasis in pregnancy.
        Lancet. 1991; 338: 1594-1595
        • Kater RM
        • Mistilis SP
        Obstetric cholestasis and pruritus of pregnancy.
        Med J Aust. 1967; 1: 638-640
        • Steel R
        • Parker ML
        Jaundice in pregnancy.
        Med J Aust. 1973; 1: 461
        • Reyes H
        • Taboada G
        • Ribalta J
        Prevalence of intrahepatic cholestasis of pregnancy in La Paz, Bolivia.
        J Chronic Dis. 1979; 32: 499-504
        • Johnston WG
        • Baskett TF
        Obstetric cholestasis. A 14 year review.
        Am J Obstet Gynecol. 1979; 133: 299-301
        • Jiang ZH
        • Qiu ZD
        • Liu WW
        • Liu YH
        • Wang QN
        • Miao HZ
        • et al.
        Intrahepatic cholestasis of pregnancy and its complications. Analysis of 100 cases in Chongqing area.
        Chin Med J. 1986; 99: 957-960
        • Qiu ZD
        • Wang QN
        • Liu YH
        • Miao HZ
        Intrahepatic cholestasis of pregnancy. Clinical analysis and follow-up study of 22 cases.
        Chin Med J. 1983; 96: 902-906
        • Perreau P
        • Rouch R
        Ictere cholestatique recidivant de la grossesse.
        Gynecol Obstet. 1961; 60: 161-179
        • Gagnaire JC
        • Descos L
        • Magnin P
        Signification du prurit au cours de la grossesse.
        Nouv Presse Med. 1975; 4: 1105-1108
        • Roger D
        • Vaillant L
        • Fignon A
        • Pierre F
        • Bacq Y
        • Brechot JF
        • et al.
        Specific pruritic diseases of pregnancy. A prospective study of 3192 pregnant women.
        Arch Dermatol. 1994; 130: 734-739
        • Roszkowski I
        • Wojcicka J
        Jaundice in pregnancy. I. Biochemical assays.
        Am J Obstet Gynecol. 1968; 102: 839-846
        • Brites D
        • Rodrigues CM
        • van-Zeller H
        • Brito A
        • Silva R
        Relevance of serum bile acid profile in the diagnosis of intrahepatic cholestasis of pregnancy in a high incidence area: Portugal.
        Eur J Obstet Gynecol Reprod Biol. 1998; 80: 31-38
        • Cahill KM
        Hepatitis in pregnancy.
        Surg Gynecol Obstet. 1962; 114: 545
        • Wilson BR
        • Haverkamp AD
        Cholestatic jaundice of pregnancy: new perspectives.
        Obstet Gynecol. 1979; 54: 650-652
        • Van Dyke RW
        The liver in pregnancy.
        in: Zakim D Boyer TD Hepatology. A Textbook of Liver Disease. W.B. Saunders, Philadelphia1996: 1734-1759