Fetal sulfated and nonsulfated bile acids in intrahepatic cholestasis of pregnancy.

Nonsulfated the sulfated bile acids were determined in maternal and umbilical cord serum, amniotic fluid, and meconium samples in pregnancies complicated by maternal intrahepatic cholestasis, and the results were compared with those obtained in uncomplicated pregnancy. The serum levels of nonsulfated and sulfated bile acids were elevated in both maternal and fetal serum in cholestasis pregnancies, and there was a considerable maternal-to-fetal difference in their levels across the placenta, the lower values being in the fetal compartment. The proportion of sulfate conjugates of the total serum bile acids was similar in both compartments, about 10%. In amniotic fluid low levels of cholic and chenodeoxycholic acid were found in uncomplicated pregnancies. In the cholestasis pregnancies amniotic fluid bile acid levels were elevated, especially that of cholic acid. The swallowing of considerable amounts of bile salt by the fetus with the amniotic fluid leads to an increased accumulation of bile salt in the meconium in cholestasis. The proportion of sulfate-conjugated bile acids was large in the meconium samples in both uncomplicated and cholestasis pregnancies.