Hepatitis E virus (HEV) infection causes severe maternal and fetal outcomes in pregnant women. These patients are exclusively from resource-limited regions with genotype 1 HEV infection, but not from western countries with genotype 3 prevalence. Since the circulating strains in China have evolved from the waterborne genotype 1 to the zoonotic genotype 4 HEV in the past decades, this study aims to evaluate the prevalence and clinical features of HEV infection in a large cohort of pregnant women in Inner Mongolia, China.

A total of 3278 pregnant women who visited the Inner Mongolia Maternal and Child Care hospital during 2018 were enrolled. Serum samples were examined for anti-HEV IgG and anti-HEV IgM antibodies using ELISA. Demographic information, results of clinical biochemical tests, maternal and neonatal outcomes were collected.

Among the recruited 3278 pregnant women, 6.0% were anti-HEV IgG antibody positive, 0.3% were anti-HEV IgM antibody positive and 0.3% were positive for both anti-HEV IgG and anti-HEV IgM antibodies. HEV viral RNA was not detected. Pregnant women with recent/ongoing HEV infection indicated by anti-HEV IgM positivity have slightly higher ALT level, and potential risk of developing hyperlipidemia, preterm delivery and neonatal jaundice.

These findings indicated that HEV infection is associated with a possible increase in adverse maternal, fetal and neonatal outcomes in our cohort. Thus, the burden of HEV infection in pregnant women in China appears distinct from resource-limited regions and western countries. Nevertheless, future studies are required to confirm and extend our findings.