The effect of rupture of membranes and labour on the risk of hepatitis B vertical transmission: Prospective multicentre observational study.

OBJECTIVE: To evaluate the effect of rupture of membranes and labour on the risk of hepatitis B virus (HBV) vertical transmission. STUDY DESIGN: A prospective multicentre observational study was carried out in Hong Kong between 2014-2016. Pregnant HBV carriers were recruited. The duration of rupture of membranes, labour and mode of delivery were collected prospectively. HBV DNA was examined at 28-30 weeks of gestation. All newborns received standard HBV vaccination and immunoglobulin. Hepatitis B surface antigen of infants was tested at 9-12 months of age. RESULTS: 641 pregnancies were recruited and analyzed. No statistically significant difference was found in gravida, parity, gestational age at delivery, mode of delivery, duration of rupture of membranes, duration of labour, preterm delivery, preterm rupture of membranes or birth weight (p > 0.05). Subgroup analysis in viral load > 7log10IU/ml and 8log10IU/ml also did not find a significant association between duration of rupture of membranes and labour with immunoprophylaxis failure. CONCLUSIONS: Duration of rupture of membranes and labour would not affect the risk of HBV vertical transmission in infants following standard HBV vaccination and hepatitis B immunoglobulin administration.