Maternal viral load and hepatitis B virus mother-to-child transmission risk: A systematic review and meta-analysis

Aim: The aim of this study was to assess the relationship between maternal viral load and mother-to-child transmission (MTCT) risk in hepatitis B envelope antigen (HBeAg)-positive mothers.

Methods: PubMed and Web of Science were systematically searched. We compared MTCT incidence between maternal hepatitis B virus (HBV)-DNA-positive and HBV-DNA-negative groups. We also examined the dose-response effect of this relationship.

Results: Twenty-one studies with 10 142 mother-child pairs were included in the studies. The mean MTCT incidence was 13.1% in the maternal HBV-DNA-positive group, compared with 4.2% in the negative group. The summary MTCT odds ratio of maternal HBV-DNA positive compared with negative was 9.895 (95% confidence interval [CI], 5.333 to 18.359; Z = 7.27, P < 0.00001) by random-effects model. In maternal HBV-DNA <6 log10 copies/mL, 6-8 log10 copies/mL, and >8 log₁₀ copies/mL level stratifications, the pooled MTCT incidences were 2.754% (95% CI, 1.198-4.310%; Z = 3.47, P = 0.001), 9.932% (95% CI, 6.349-13.516%; Z = 5.43, P < 0.00001), and 14.445% (95% CI, 8.317-20.572%; Z = 4.62, P < 0.00001), respectively. A significant linear dose-response association was found between maternal viral load and MTCT risk, with the points estimate of increased MTCT risk 2.705 (95% CI, 1.808-4.047) at 6 log10 copies/mL compared with reference (3 log10 copies/mL), and 7.316 (95% CI, 3.268-16.378) at 9 log₁₀ copies/mL. A significant non-linear dose-response association was also found between maternal viral load and HBV MTCT risk (model χ² = 23.43, P < 0.00001).

Conclusion: Our meta-analysis indicated that maternal viral load was an important risk factor for MTCT in HBeAg-positive mothers, and maternal viral load was dose-dependent with HBV MTCT incidence.