A double-blind, randomized, placebo-controlled trial of acyclovir in late pregnancy for the reduction of herpes simplex virus shedding and cesarean delivery

OBJECTIVE: The purpose of this study was to assess the efficacy of acyclovir in the reduction of herpes simplex virus culture and polymerase chain reaction positivity and cesarean delivery. STUDY DESIGN: Women with recurrent genital herpes simplex virus Were randomized to acyclovir 400 mg three times daily or placebo from 36 weeks of gestation until delivery. A subset of daily specimens for herpes simplex virus culture and DNA polymerase chain reaction was self-collected. Analyses used chi(2), Fisher exact, and Mann-Whitney U tests. RESULTS: Lesions occurred at delivery among 11 of 78 women (14%) who received placebo and 4 of 84 women (5%) who received acyclovir (P = .08). Herpes simplex virus culture and polymerase chain reaction positivity near delivery occurred in 7% and 34% women in the placebo group and 0 and 2% in the acyclovir group (P = .03 and < .01, respectively). Cesarean delivery for herpes simplex virus occurred in 8 of the women (10%) in the placebo group and in 3 of the women (4%) in the acyclovir group (P = .17). Despite reductions in herpes simplex virus detection, 6% of the women who received acyclovir had herpes simplex virus detected by polymerase chain reaction on >20% of days. Neonatal outcomes were similar between groups. CONCLUSION: Acyclovir significantly reduced, but did not eliminate, herpes simplex virus lesions and detection in late pregnancy.