Pregnancy and maternal chronic hepatitis B infection-Evidence of reproductive advantage?

PROBLEM: As multiparas have high prevalence of chronic hepatitis B virus (HBV) infection, we examined here the relationship between the number of pregnancies with HBV infection.

METHOD OF STUDY: Retrospective cohort study examining the prevalence of HBV infection by actual gravidity and parity in 104 242 gravidae managed during 1997-2013.

RESULTS: Infection rate increased from 8.5% to 10.6% for G1 to G≥6 and from 8.8% to 10.0% for P0 to P≥3 (P<.001). When stratified by parity, correlation with gravidity was maintained in the nulliparous gravidae. For the same gravidity, increasing parity was associated with higher rate of HBV infection for G2 and G3. Multiparas had higher HBV infection prevalence (all >10%) than nulliparas (<10%) for G2 to G≥4.

CONCLUSION: Prior pregnancies, especially successful ones, are associated with increased HBV infection in an endemic population, which could have enhanced reproduction and in the process facilitated its transmission to the following generations.