Follow-up of pregnant women at high risk of transmitting herpes simplex virus.

Prospects for neonatal herpes transmission were studied in a group of pregnant Chilean women at high herpetic risk--including 59 with a history of genital herpes, 11 with a first genital herpes episode during the observed pregnancy, and 16 whose sexual partners had a history of genital herpes. Each woman completed a survey questionnaire, provided serologic samples for detection of herpes simplex virus (HSV), and provided periodic samples taken with cotton swabs for HSV isolation. The 86 women who completed the study had an average age of 28 years; most (58.8%) were primiparas. Only 21 of the 86 subjects yielded HSV isolates (predominantly HSV-2) from weekly cotton swab samples taken from the 34th week of pregnancy onward. HSV-2 predominance was found both in the symptomatic cases and in the three asymptomatic ones. Of six subjects found to be shedding HSV at the time of delivery, only one exhibited asymptomatic shedding. These findings are consistent with the following conclusions derived from studies in developed countries: (1) Isolation of HSV in pregnancy does not define a greater risk of shedding HSV during childbirth. (2) In nearly all (five of six) cases, HSV shedding during childbirth involved symptomatic episodes of herpes that clearly defined the steps to be taken by the physician. (3) Despite this, the finding of one asymptomatic case demonstrates that the physician should request a test for HSV isolation at the time of delivery by a woman at high herpetic risk.