False-positive amniotic fluid cytology in a parturient with active genital herpes infection at term.

A patient who developed genital herpes infection diagnosed at 37 weeks' gestation is presented. Amniocentesis performed at 38 weeks' gestation revealed herpetic changes in fetal cells. Subsequent amniotic fluid viral culture was negative. The infant was delivered by elective primary cesarean section at 39 weeks' gestation, demonstrated no evidence of herpetic infection, and was well at a 3-month follow-up examination. Positive cytologic changes seen in epithelial cells obtained by amniocentesis do not necessarily indicate intrauterine infection of the fetus. Cytologic changes alone are inadequate, and viral isolation by culture or by immunofluorescence should be required before prophylactic cesarean section is abandoned in the treatment of the parturient with active genital herpes infection near term.