Maternal pre-pregnancy infection with hepatitis B virus andudthe risk of preterm birth: a population-based cohort study

摘要

Background Preterm birth is the leading cause of child death in children younger than 5 years. Large cohort studies inuddeveloped countries have shown that maternal hepatitis B virus infection is associated with preterm birth, but thereudis little reliable evidence from China and other developing countries, where hepatitis B virus prevalence is intermediateudor high. Hence, we designed this study to investigate the association between pre-pregnancy hepatitis B virus infectionudand risk of preterm and early preterm birth.udMethods Between Jan 1, 2010, and Dec 31, 2012, we did a population-based cohort study using data from 489 965 ruraludwomen aged 21–49 years who had singleton livebirths from 220 counties of China who participated in the NationaludFree Preconception Health Examination Project. Participants were divided into three groups according to their prepregnancyudstatus of hepatitis B virus infection: women uninfected with hepatitis B virus (control group), women whoudwere HBsAg positive and HBeAg negative (exposure group 1), and women who were both HBsAg and HBeAg positiveud(exposure group 2). The primary outcome was preterm birth (gestation at less than 37 weeks). We used log-binomialudregression to estimate adjusted risk ratios (aRR) of preterm birth for women with pre-pregnancy hepatitis B virusudinfection, and risk of early preterm birth (gestation less than 34 weeks).udFindings 489 965 women met inclusion criteria and were included in this study; of these, 20 827 (4·3%) were infectedudwith hepatitis B virus. Compared with women who were not infected with hepatitis B virus, women who were HBsAgudpositive and HBeAg negative had a 26% higher risk of preterm birth (aRR 1·26, 95% CI 1·18–1·34) and women whoudwere both HBsAg and HBeAg positive had a 20% higher risk of preterm birth (aRR 1·20, 1·08–1·32). Compared withudwomen who were not infected with hepatitis B virus, women who were HBsAg positive and HBeAg negativeudmanifested an 18% higher risk of early preterm birth (gestation less than 34 weeks; aRR 1·18, 1·04–1·34) and womenudwho were both HBsAg and HBeAg positive had a 34% higher risk of early preterm birth (aRR 1·34, 1·10–1·61).udMaternal pre-pregnancy hepatitis B virus infection was independently associated with higher risk of preterm birthudand early preterm birth. These associations were similar in subgroups of participants as defined by baselineudcharacteristics.udInterpretation Besides mother-to-child transmission, the risk of preterm birth in women infected with hepatitis Budvirus should not be neglected. Comprehensive programmes that focus on early detection of hepatitis B virus infectionudbefore pregnancy and provide appropriate medical intervention for women infected with hepatitis B virus before andudduring pregnancy would be helpful in improving maternal and neonatal outcomes and reducing child mortality.