Shahar-Nissan K, Pardo J, Peled O, et al. - Researchers examined if valaciclovir is capable of preventing vertical transmission of cytomegalovirus to the fetus in pregnant women with a primary infection acquired early in pregnancy. In this prospective, randomized, double-blind, placebo-controlled trial, they randomized 100 pregnant women (aged 18 years or older) with serological evidence of a primary cytomegalovirus infection acquired either periconceptionally or during the first trimester of pregnancy, to receive valaciclovir or placebo from enrollment until amniocentesis at 21 or 22 gestational weeks. Reduction in the rate of fetal cytomegalovirus infection after maternal primary infection acquired early in pregnancy was observed in correlation with receiving valaciclovir. Findings suggest that providing early treatment in pregnant women with primary infection might result in prevention of termination of pregnancies or delivery of infants with congenital cytomegalovirus.