Obstetric patients with a history of recurrent herpes simplex infection should be treated with acyclovir 400 mg orally 3 times daily from 36 weeks until delivery. This regimen significantly reduces the likelihood of a recurrent outbreak near the time of delivery, which if it occurred, would necessitate a cesarean delivery. In patients at increased risk for preterm delivery, the prophylactic regimen should be started earlier.
Valacyclovir, 500 mg orally twice daily, is an acceptable alternative but is significantly more expensive.