Maternal HBV infection raises preterm birth risk
medwireNews: Women with hepatitis B virus (HBV) infection prior to becoming pregnant are significantly more likely to have a preterm birth than those without HBV, shows an analysis of a Chinese population-based cohort.
“Comprehensive programmes that focus on the early detection of hepatitis B virus infection before pregnancy, monitor the risk of preterm birth, and provide appropriate medical intervention for women infected with hepatitis B virus during pregnancy would be helpful in improving maternal and neonatal outcomes and reducing child mortality,” the investigators write.
They explain that previous research into the association between maternal HBV infection and preterm births has mainly been conducted in developed countries and has yielded inconsistent results. The team adds that “little reliable evidence exists from China or other developing countries where the prevalence of hepatitis B virus infection is intermediate or high.”
The current study included 489,965 women aged 21–49 years who participated in China’s National Free Preconception Health Examination Project and who had a singleton live birth between 2010 and 2012. Of these, 3.1% tested positive for hepatitis B surface antigen (HBsAg), but negative for hepatitis B e antigen (HBeAg), prior to becoming pregnant, while 1.2% were positive for both HBsAg and HBeAg.
After adjusting for factors such as the history of pregnancy and adverse pregnancy outcomes, the risk for preterm birth (<37 weeks gestation) was a significant 26% higher for women who were HBsAg-positive than for controls (p<0.0001), whereas those who were HBsAg- and HBeAg-positive had a significant 20% higher risk (p=0.0006).
The early preterm birth (<34 weeks gestation) risk was similarly elevated for women with HBV compared with the controls, at a significant 18% and 34% higher for women positive for HBsAg alone and those positive for both HBsAg and HBeAg, respectively (p=0.0095 and 0.0025).
Study author Min Liu, from Peking University in Beijing, China, and colleagues speculate that “the association between maternal hepatitis B virus infection and preterm birth might be explained by the accumulation of hepatitis B virus DNA in the placenta and trophoblast cells that might initiate the placental inflammatory response, a known contributor to preterm birth.”
But they add that further research into the underlying mechanisms is needed.
Writing in a commentary accompanying the research in The Lancet Global Health, Qi-Tao Huang and Mei Zhong (both from Southern Medical University, Guangzhou, China) think that it might also “be worthwhile to explore the dose–response relation between hepatitis B virus DNA load and preterm birth, as well as other pregnancy-related complications.”
Moreover, given that antiviral therapy during the second or third trimester in women with a high HBV load has been shown to reduce vertical transmission, the commentators believe “it would be helpful to investigate whether anti-hepatitis B virus therapy could have additional health benefits, such as lowering the risk of preterm birth.”
By Shreeya Nanda
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