Background: Neonatal herpes is a rare, devastating consequence of herpes simplex virus type 1 (HSV-1) or 2 (HSV-2) infection during pregnancy. The risk of neonatal infection is higher among pregnant women seronegative for HSV-1 or HSV-2 who acquire their first HSV infection near delivery.
Methods: We estimated HSV-1 and HSV-2 seroprevalence among pregnant women aged 20-39 years in 1999-2014, assessed HSV seroprevalence changes between 1999-2006 and 2007-2014, and compared HSV seroprevalence between pregnant women and sexually active, nonpregnant women aged 20-39 years in 2007-2014 using National Health and Nutrition Examination Survey data.
Results: Among pregnant women in 1999-2014, HSV-1 seroprevalence was 59.3%, HSV-2 seroprevalence was 21.1%, and HSV seronegativity was 30.6%. Between 1999-2006 and 2007-2014, HSV-1 and HSV-2 seroprevalence among pregnant women remained stable. However, among pregnant women with ≤3 sex partners (approximately 40% of all pregnant women), seronegativity for both HSV-1 and HSV-2 increased from 35.6% to 51.4% (P < .05). In 2007-2014, nonpregnant women who were (1) unmarried, (2) living below poverty level, or (3) had ≥4 sex partners were more likely than pregnant women to be seronegative for both HSV-1 and HSV-2 (P < .05).
Conclusions: HSV-1 and HSV-2 seroprevalence among US pregnant women remained stable between 1999 and 2014. However, pregnant women with fewer sex partners were increasingly seronegative for both HSV-1 and HSV-2, indicating an increasing proportion of pregnant women who are vulnerable to primary HSV acquisition in pregnancy, which confers an increased risk of transmitting HSV to their neonates.