Bile acid levels and risk of adverse perinatal outcomes in intrahepatic cholestasis of pregnancy: A meta-analysis

Aim: We aimed to determine the association between maternal total bile acid (TBA) levels and the risks of adverse perinatal outcomes in pregnant women with intrahepatic cholestasis of pregnancy (ICP) based on a meta-analysis study. Methods: We searched PubMed for articles published from 2000 to 2015 with a focus on ICP and restriction to the English language. The main perinatal outcomes were preterm birth (PTB), meconium-stained amniotic fluid (MSAF), asphyxia, or respiratory distress syndrome (RDS). Relative risk (RR) with 95% confidence intervals (CI) was the summary statistic. We used a random- or fixed-effects model to calculate the pooled RR according to the heterogeneity test. Subgroup analyses were performed by region and study design. Results: Nine eligible related citations fulfilled the inclusion criteria and were included in this study. Compared with pregnant women with a serum TBA < 40mol/L, severe ICP (TBA 40 mol/L) was associated with a significantly increased risk of adverse fetal outcomes (pooled RR,1.96; 95%CI, 1.63-2.35), PTB (pooled RR,2.23; 95% CI, 1.51-3.29), MSAF (pooled RR, 2.27; 95% CI, 1.81-2.85), and asphyxia or RDS (pooled RR, 1.67; 95%CI, 1.18-2.36). Sensitivity analysis suggested that the study design difference may be a major source of heterogeneity. No publication bias was demonstrated by Begg's test (P > 0.05). Conclusion: This meta-analysis indicates that maternal elevated bile acid levels are significantly associated with increased risks of overall adverse perinatal outcomes, PTB, MSAF, and asphyxia or RDS. Serum TBA levels seem to be a useful predictor for the risk of adverse perinatal outcomes.