BACKGROUND: Hepatitis E virus (HEV) infection during pregnancy is associated with obstetric complications and adverse maternal and neonatal outcomes. This study aimed to determine the seroprevalence of HEV and RNA positivity in both healthy pregnant women and women coinfected with hepatitis B virus (HBV). METHODS: A cross-sectional study was conducted involving 528 pregnant women (278 with and 250 without hepatitis B surface antigen [HBsAg]) in their third trimester. Anti-HEV specific immunoglobulin (Ig) G and IgM antibodies were tested for using enzyme-linked immunosorbent assay, while HEV RNA was detected by means of nested polymerase chain reaction. The status of anti-HEV antibodies was analyzed regarding pregnancy outcomes and the risks of obstetric complications. RESULTS: The results indicated that 24% of participants (127 of 528) tested positive for anti-HEV IgG, while 2.5% (13 of 528) showed detectable anti-HEV IgM. Among HBV-positive women, 26% (55 of 250) had anti-HEV IgG, comparable to 22% (61 of 278) in HBV-negative controls. Notably, 28% (140 of 501) of cord blood samples were positive for anti-HEV IgG. No cases of HEV RNA were detected. The prevalence of anti-HEV IgG increased with maternal age and was associated with higher infant birth weights. Anti-HEV IgM positivity was associated with an increased risk of neonatal infections (odds ratio, 20.6
CONCLUSIONS: These findings highlight the endemic nature of HEV in Vietnam and underscore the potential risks of coinfection with HBV during pregnancy, which may lead to adverse obstetric outcomes.