Objective: To establish the prevalence of intrahepatic cholestasis of pregnancy (ICP) in a primarily Latina population in the United States.
Study design: Over a period of 16 months, a convenience sample of subjects admitted to labor and delivery in the third trimester was enrolled. Each subject completed a questionnaire rating their severity of pruritus on a numeric scale of 1 to 10. Serum was analyzed via radioimmunoassay for total bile acid concentration. ICP was defined as pruritus score >4 and a total serum bile acid concentration of >or=20 micromol/l. Ethnicity was determined from hospital record demographic data.
Results: All invited participants enrolled in the study. Three hundred and forty subjects were enrolled. Three hundred and sixteen subjects (93%) were identified as Latina. The serum bile acid concentration range for the entire study population was 1 to 580 micromol/l with a mean of 10.4+/-34.9 micromol/l. Twenty-four (7.1%) subjects had a serum bile acid concentration >or=20 micromol/l. A pruritus score >4 was found in 19.7% (67/340). Of the 24 subjects with a bile acid concentration >or=20 micromol/l, 19 also had a pruritus score >4. Thus, the prevalence of ICP in this population was 5.6% (19/340). In subjects with ICP, the mean serum bile acid concentration was 89.5+/-124.0 micromol/l. When controlling for confounders, women with ICP were associated with higher rates of chorioamnionitis (P=0.043) and their fetuses had higher rates of thick meconium (P=0.053).
Conclusions: The overall prevalence of ICP in this population was 5.6%, 10 to 100 times higher than previously reported data from the United States. Larger studies of perinatal morbidity examining the diagnostic criteria of cholestasis need to be conducted.