Pregnant women with chronic hepatitis B virus infection at the assessment of tenofovir disoproxil fumarate prescription: Baseline characteristics of a prospective cohort study in Vietnam

Objectives: We aimed to determine epidemiological characteristics and serologic markers among chronically hepatitis B virus (HBV)-infected pregnant women during the assessment of tenofovir disoproxil fumarate (TDF) prescription in Vietnam.

Methods: We consecutively recruited 375 pregnant women with chronic HBV (cHBV) infection at week 25±2 of pregnancy, at which time they were assessed for TDF use as pre-prophylaxis and/or pre-treatment at the Hospital for Tropical Diseases in southern Vietnam during December 2019-April 2021. Demographic characteristics, serological biomarkers, and prenatal liver ultrasounds were obtained through interviews and reviews of medical records.

Results: The median age of pregnant women was 29 years (interquartile range: 26-32). More than half of pregnant women (208/375; 55.5%) started TDF for prevention of mother-to-child transmission of HBV and/or treatment of chronic hepatitis B (CHB). Among the pregnant women initiating TDF, 96.1% (198/206) tested positive for hepatitis B e antigen, and 21.6% (45/208) had quantitative hepatitis B surface antigen (qHBsAg) ≤10⁴ IU/mL. A relatively strong correlation between qHBsAg and HBV deoxyribonucleic acid (DNA) (r = 0.81; 95% CI: 0.76-0.85) was observed in pregnant women starting TDF.

Conclusions: Our results demonstrate the high need for TDF prescription for prevention and/or treatment purposes in pregnant women with cHBV infection. Pregnant women with qHBsAg levels ≤10⁴ IU/mL may prioritize HBV DNA testing over qHBsAg to decide on TDF prescription.