In this prospective study we evaluate the role of serum bile acids in the investigation and management of cholestasis of pregnancy in a detailed study of 18 patients. Bile acids were the most sensitive diagnostic test. The increased incidence of fetal distress (33.3% in this series) and meconium-stained fluid (58.3%) did not correlate with very high values of bile acids in maternal serum, umbilical cord serum, or amniotic fluid. Treatment of pruritus with cholestyramine and/or phenobarbital is ineffective in this condition, induction of labor is suggested once fetal lung maturity is established.