Cesarean section does not reduce mother-to-infant transmission of hepatitis B virus

Objective To investigate whether cesarean section on pregnant women with chronic hepatitis B virus (HBV) infection may reduce mother-to-infant transmission risk of HBV.Methods Preserved serum samples of pregnant women at 15-20 weeks of gestation which were collected from July 2002 to August 2004 in 14 counties of Jiangsu Province were analyzed retrospectively.These samples were tested for HBV serologic markers with enzyme immunoassay,and 419 cases of positive hepatitis B surface antigen (HBsAg) were found.HBV DNA level of these HBsAg-positive women were further quantitatively measured with real-time polymerase chain reaction assay.Children of these 419 HBsAg-positive mothers were followed up during October 2009 to March 2010 and 298 of them were contactable (71.1％),among which 281 were enrolled in final analysis as they had complete information and had been vaccinated with three regular doses of HBV vaccine during infantile period.The 281 children were tested for serum HBV markers.The HBV infection rate in these children at age 5-7 was compared between those born by cesarean setion (CS group,n =136) and by vaginal delivery (VD group,n=145).T-test,x2 test or Fisher's exact test was used to analyze relevant parameters.Results(1) Maternal HBeAg-positive rates [25.7％ (35/136) vs 34.5％ (50/145)],HBV DNA levels in HBeAg-positive women [(2.30 × 106) IU/ml vs (2.09× 106) IU/ml],the percentages of HBIG injection after birth [38.2％ (52/136) vs 35.9％ (52/145)],breastfeeding ratios [82.4％ (112/136) vs 75.9％ (110/145)],and children' s ages at the follow-up [(5.9 ± 0.8) vs (6.0±0.6)] were comparable between CS group and VD group (all P＞0.05).(2) Among these 281 children,272 (96.8％) were HBsAg-negative,9 (3.2％) were HBsAg-positive and 163 (58.0％) were anti-HBs-positive.The prevalence of HBsAg-positive [(2.9％ (4/136) vs 3.4％ (5/145)],HBsAg negative and anti HBc positive [0.0％ (0/136) vs 1.4％ (2/145)] and anti-HBs positive [57.4％(78/136) vs 58.6％(85/145)] in CS group were similar to those in VD group.Conclusions Cesarean section does not reduce the risk of mother-to-infant transmission of HBV.In clinical practice,elective cesarean section should not be suggested in order to prevent HBV vertical infection. Key words: Hepatitis B virus; Disease transmission, vertical; Hepatitis B; Casarean section