Can an Antiviral Prevent Vertical Transmission of Cytomegalovirus?

Maternal infection with cytomegalovirus (CMV) during early pregnancy can cause severe abnormalities in the fetus. Investigators in Israel randomized 100 women with serologically confirmed periconceptional or first-trimester CMV infection to receive oral valacyclovir (8 g taken as 4 g twice daily) or placebo. The study endpoint was presence of fetal CMV infection detected with amniocentesis at 22 weeks.

Among 90 analyzable pregnancies (92 fetuses), rates of CMV infection were 11% for fetuses in the valacyclovir group versus 30% in the placebo group (odds ratio, 0.29; 95% confidence interval, 0.09–0.90). The drug was well tolerated, without significant adverse events. Clinical sequelae of CMV infection (predominantly hearing loss) were noted i…