Herpes simplex virus infection in pregnancy.

The incidence of herpes simplex virus (HSV) infection has been climbing steadily in recent decades and concerns about perinatal HSV infection are growing among women of reproductive age because of the risk of transmission of the virus to their babies during pregnancy with potentially devastating consequences to the fetus. Neonatal infection with HSV most often occurs during labour when the baby comes into direct contact with infected maternal secretions in the birth canal. Infection can also occur while the fetus is still in utero or after birth however. The risk of vertical transmission of HSV infection can be as high as 50% in women who develop a primary infection during the third trimester. There is increasing anecdotal evidence in support of the use of aciclovir in infected pregnant patients at risk of an HSV reactivation at the time of delivery as a strategy to reduce transmission of virus from the mother to the neonate. This approach is associated with a decrease in the number of Caesarean sections required for the prevention of transmission. Trials to evaluate further the safety and efficacy of suppressive valaciclovir and famciclovir would be useful. (authors)