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Mother-to-child HBV transmission risk increases with maternal viral load

A systematic review and meta-analysis revealed that maternal viral load among mothers with hepatitis B was a significant risk factor for mother-to-child transmission, and was dose-dependent with HBV transmission incidence.

“Hepatitis B virus (HBV) infection is a major global health problem. According to WHO estimates, 240 million people are chronically infected with hepatitis B,” Hong-Lin Chen, MD, from the Nantong University, China, and colleagues wrote. “HBV infection acquired via mother-to-child transmission (MTCT) is typically considered to be one of the major causes of chronic infection.”

Chen and colleagues identified 21 studies with 10,142 mother-child pairs for evaluation. Most studies were published within the previous 10 years and were conducted in China. Mother-to-child transmission incidence ranged from 1.54% to 45.5%.

Mean mother-to-child transmission incidence in patients positive for HBV DNA was 13.1% (range, 3.1%-81.5%), compared with 4.2% (range, 0%-39.4%) among mothers negative for HBV DNA. Mothers positive for HBV DNA had a significantly higher risk for transmission to child (OR = 9.895; 95% CI, 5.333-19.359). The researchers found significant heterogeneity between studies (P < .00001), although there was evidence of publication bias.

The researchers conducted a subgroup analysis of mother-to-child transmission incidence by HBV DNA level. Among mothers with HBV DNA less than 6 log₁₀ copies/mL, the researchers found that incidence ranged from 0% to 6.7% and pooled incidence was 2.754% (95% CI, 1.198-4.31). Mothers with HBV DNA higher than 8 log₁₀ copies/mL had an incidence range from 7.6% to 33.3% and pooled incidence of 14.445% (95% CI, 8.317-20.572).

Finally, the researchers found that linear dose-response showed significant and evolutionary risk of mother-to-child transmission of HBV along increased maternal viral load (OR = 1.393; 95% CI, 1.218-1.594) for each log₁₀ copy/mL increase. Compared with a reference of 3 log₁₀ copies/mL, the odds ratio for transmission increased from 2.705 (95% CI, 1.808-4.047) among mothers with a viral load of 6 log₁₀ copies/mL to 7.316 (95% CI, 3.268-16.378) among those with a viral load of 9 log₁₀ copies/mL.

“Lowering the level of maternal HBV DNA during pregnancy is momentous for the prevention of MTCT in mothers with high viremia. However, there is still no consensus on the optimal cut-off value of maternal viral load for antiviral treatment,” the researchers wrote. “The result indicated the newborns still at risk when HBV DNA [less than] 6 log₁₀ copies/mL. So, we think antiviral treatment maybe given when mothers with positive HBV DNA, rather than [higher than] 6 log₁₀ copies/mL. However, this inference should be confirmed by other randomized controlled [trials].” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.