Chinese pregnant women in their third trimester are more susceptible to HEV infection.

HEV is one of the most important causes of acute clinical hepatitis in adults with particularly high mortality in pregnant women in developing countries, such as China.1 Although low seroprevalence of HEV infection in pregnant women was reported in Kunming City, Yunnan Province, China in 2011,2 an outbreak of HEV occurred in the city in 2015 affecting both pregnant women and general population. In the present study, the prevalence of HEV was investigated in Kunming city by ELISA and RT-PCR methods. Results indicated that HEV infection epidemic in Kunming city was associated with swine HEV, and pregnant women in their third trimester were more susceptible to HEV infection. Serum samples of asymptomatic pregnant women (n = 274, 90 samples in the first, 92 samples in the second, and 92 samples in the third trimesters of pregnancy) and general population (n = 114) were collected for HEV antibodies and HEV RNA detection from January to April 2015. IgM antibody was detected during the acute stage of HEV infection. Among samples of the pregnant women, 10 sera (10/274, 3.65%) were positive to HEV IgM, which was similar to the general population in 2015 (5/114, 4.39%), but higher than that in 2011 in the same city (4/293, 1.37%),2 and Shandong Province, China in 2011–2013 (2.6%).3 Surprisingly, 90% of pregnant women positive for HEV IgM antibody (9/10) were in their third trimester of pregnancy, which was significantly higher than in other stages of pregnancy (Table 1). Furthermore, the activity of AST in HEV IgM positive pregnant women (40–20 IU/L) was higher than that in general population