Liver Dysfunction during Pregnancy and Its Association With Preterm Birth in China: A Prospective Cohort Study

BACKGROUND: Liver dysfunction is common in pregnancy but its association with adverse pregnancy outcomes such as preterm birth (PTB) remains unclear. METHODS: A prospective cohort of HBV-infected or uninfected pregnant women attending antenatal care was recruited at Nantong Maternal and Child Health Hospital between January 1, 2012, and June 30, 2016. Liver function tests (LFTs) were monitored through pregnancy. The primary outcomes were PTB and very PTB (delivery prior 37 and 32 weeks' gestation respectively). Poisson regression was used to estimate adjusted risk ratios (RR) for women with HBV infection and LFT abnormalities. RESULTS: Among 36,755 pregnant women (1,113 HBV carriers and 35,642 non-HBV subjects), 3,519 (9.57%) had abnormal LFTs. The commonest cause for liver dysfunction during pregnancy was non-alcoholic fatty liver diseases (NAFLD, 51.3%). Abnormal aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and two folds upper limit of normal total bilirubin (RR and 95%CI: 2.73, 1.30–5.76; 2.24, 1.35–3.31; 2.01, 1.22–3.31 respectively), rather than HBsAg positivity, were identified as independent risk factors for preterm birth. Besides, GGT abnormality was associated with increased risk of very PTB. CONCLUSIONS: We suggest that surveillance of LFTs among pregnant women should be warranted, given the increased risk of PTB.