Beyond stillbirth: association of intrahepatic cholestasis of pregnancy severity and adverse outcomes

Abstract

Background: Intrahepatic cholestasis of pregnancy is associated with adverse pregnancy outcomes, including sudden fetal cardiac arrhythmias, resulting in stillbirth. This association has been correlated with the total bile acid levels, which are a marker for disease severity. Studies are yet to determine if intrahepatic cholestasis of pregnancy severity is also associated with increased rates of other adverse neonatal outcomes.

Objective: This study aimed to determine whether pregnancies complicated by intrahepatic cholestasis of pregnancy show a bile acid severity-based relationship with other adverse obstetrical outcomes beyond stillbirth alone.

Study design: This was a retrospective cohort study of singleton, nonanomalous gestations complicated by intrahepatic cholestasis of pregnancy at the Elmhurst Hospital Center from 2005 to 2019. Severity was defined by the peak total bile acid levels (μmol/L): mild (10-19), low moderate (20-39), high moderate (40-99), and severe (>100). We examined the rates of spontaneous preterm labor, fetal growth restriction, preterm prelabor rupture of membranes, iatrogenic preterm birth, meconium-stained amniotic fluid, cesarean delivery for nonreassuring fetal heart tracing, umbilical artery pH, neonatal intensive care unit admission, and neonatal birthweight. The chi-square, Fisher exact, Student t, Mann-Whitney, and multivariate regression tests were used to determine the association of intrahepatic cholestasis of pregnancy severity and adverse neonatal outcomes. In all analyses, mild severity was used as the base comparator. A P value of <.05 and 95% confidence interval not crossing 1.00 indicated statistical significance.

Results: Of the 1202 pregnancies complicated by intrahepatic cholestasis of pregnancy, 306 (25.5%) were mild, 449 were low moderate (37.4%), 327 were high moderate (27.2%), and 120 were severe (10.0%). After adjusting for confounders, progressive intrahepatic cholestasis of pregnancy severity was associated with an increased risk of spontaneous preterm labor (low moderate adjusted odds ratio, 1.60; 95% confidence interval, 0.76-3.38; high moderate adjusted odds ratio, 3.49; 95% confidence interval, 1.69-7.22; severe adjusted odds ratio, 6.58; 95% confidence interval, 2.97-14.55), iatrogenic preterm birth (low moderate adjusted odds ratio, 1.54; 95% confidence interval, 0.95-2.52; high moderate adjusted odds ratio, 3.11; 95% confidence interval, 1.91-5.06; severe adjusted odds ratio, 4.94; 95% confidence interval, 2.81-8.71), and meconium-stained amniotic fluid (low moderate adjusted odds ratio, 1.33; 95% confidence interval, 0.75-2.36; high moderate adjusted odds ratio, 2.63; 95% confidence interval, 1.48-4.65; severe adjusted odds ratio, 3.91; 95% confidence interval, 1.98-7.69). There was no significant association between intrahepatic cholestasis of pregnancy severity and other adverse outcomes.

Conclusion: The findings suggest that intrahepatic cholestasis of pregnancy disease severity is associated with an increased risk of spontaneous preterm labor, iatrogenic preterm birth, and meconium-stained amniotic fluid. These findings provide valuable insight toward patient anticipatory counseling.

Keywords: bile acids; intrahepatic cholestasis of pregnancy; intrauterine fetal demise; itching; meconium; pregnancy; pruritis; spontaneous preterm labor; ursodiol.