Risk factors for herpes simplex virus transmission to pregnant women: a couples study.

Objective: This study was undertaken to determine risk factors for herpes simplex virus (HSV) acquisition among at risk pregnant women.

Study Design: Women in a prospective study of HSV acquisition in pregnancy invited their sexual partners for HSV type-specific serologic testing. Risk factors for HSV susceptibility, exposure, and acquisition were examined.

Results: A total of 3192 couples enrolled; 22% included women at risk for HSV-1 or HSV-2. Among 582 HSV-1 seronegative women with HSV-1 seropositive partners, 14 (3.5% adjusted for gestation length) acquired HSV-1. Having a partner with a history of oral herpes was associated with HSV-1 acquisition (odds ratio [OR] 8.1, 95% CI: 1.8-36.0) and accounted for 75% of incident infections. Among 125 HSV-2 seronegative women with HSV-2 seropositive partners, 17 (20% adjusted for gestation length) acquired HSV-2. Duration of partnership of 1 year or less was associated with HSV-2 acquisition (OR 7.8, 95% CI: 2.3-25.7) and accounted for 63% of incident infections. No combination of clinical characteristics could identify the majority of susceptible women with serologically discordant partners.

Conclusion: HSV acquisition rates in pregnancy are high in discordant couples, especially for HSV-2. Interventions that address risk factors for HSV acquisition should be studied in pregnancy. Clinical profiles cannot replace serologic screening to identify susceptible women with serologically discordant partners.