Intrahepatic cholestasis of pregnancy and associated adverse pregnancy and fetal outcomes: a 12-year population-based cohort study.

OBJECTIVE To determine the risk for adverse pregnancy and fetal outcomes in intrahepatic cholestasis of pregnancy (ICP). DESIGN Population-based cohort study. SETTING Swedish Medical Birth Register (MBR) 1997-2009. POPULATION A total of 1,213,668 singleton deliveries. METHODS Linkage of Hospital Discharge Register for exposure (ICP; n=5,477) with MBR for covariates. MAIN OUTCOME MEASURES Gestational diabetes, pre-eclampsia, prematurity, and stillbirth. RESULTS Intrahepatic cholestasis (ICP) was diagnosed in 0.32-0.58% of all pregnancies, with an increasing trend until 2005 (P<0.0001). Compared with women who did not have ICP, women with ICP were more likely to have gestational diabetes (adjusted odds ratio, aOR, 2.81; 95% CI 2.32-3.41) and pre-eclampsia (aOR 2.62, 95% CI 2.32-2.78). Women with ICP were also more likely to have spontaneous (aOR 1.60, 95% CI 1.47-1.93) and iatrogenic (aOR 5.95, 95% CI 5.23-6.60) preterm delivery, with increased rates of induction of labour (aOR 11.76, 95% CI 11.04-11.62). However, this actively managed cohort of ICP cases was not at increased risk of stillbirth (aOR 0.92, 95% CI 0.52-1.62). Infants in ICP deliveries were more likely to have a low (<7) 5-minute Apgar score (aOR 1.45, 95% CI 1.14-1.85) and be large for gestational age at birth (aOR 2.27, 95% CI 2.02-2.55). CONCLUSIONS Over time, a greater proportion of Swedish pregnant women have received a diagnosis of ICP, probably because of an increased awareness of the disorder. Our data confirm an increased risk of preterm delivery, but not of stillbirth, in actively managed ICP. The high rates of gestational diabetes and pre-eclampsia are new findings, and need to be considered in the management of ICP pregnancies.