Four published RCTs (n=789 women) were included. Sample sizes ranged from 97 to 244. Studies were all performed in China and all except one trial were written in Chinese. None of the quality criteria were met: description of the randomisation procedure, concealment of allocation or details on attrition and the studies were all scored C (high risk of bias).
The rate of mother to child transmission of HBV was significantly reduced with elective caesarean section when compared to vaginal delivery (RR 0.41, 95% CI 0.28 to 0.6, p<0.000001). Subgroup analyses reported a significant reduction in HBV infection in neonates for umbilical cord blood (RR 0.5, 95% CI 0.26 to 0.95, p=0.03; one study) and peripheral blood (RR 0.37, 95% CI 0.24 to 0.59, p<0.0001; three studies).
Morbidity was not reported in the included trials.