Valacyclovir in primary maternal CMV infection for prevention of vertical transmission: A case-series

No treatment is currently approved for cytomegalovirus infection in pregnancy. Valacyclovir has been studied in symptomatic cytomegalovirus infected fetuses and seems to reduce the risk of serious sequelae.

We used off-label valacyclovir on pregnant women with primary cytomegalovirus infection to reduce the risk of fetal infection.

We treated 12 pregnant women with 8 g/day valacyclovir after diagnosis of cytomegalovirus infection until amniocentesis. We continued treatment until delivery in case of fetal infection. We periodically performed serology and virology tests on the women from referral until delivery and monitored them for adverse effects while on treatment. All women underwent late amniocentesis. We followed up infants for 5-28 months.

At the time of amniocentesis, we observed a transmission rate of 17 %, and at birth we observed a transmission rate of 42 %. Two women with negative amniocentesis and infected newborns had viremia reactivation after valacyclovir discontinuation. We observed no symptomatic infections at birth and one isolated sensory-neural hearing loss at follow-up.

This is the first series of antiviral treatment in women with a diagnosis of cytomegalovirus infection before amniocentesis. Valacyclovir may control cytomegalovirus infection while it is administered and reduce transmission at amniocentesis. Late transmission after treatment discontinuation is a risk. We advocate the need for a controlled trial of valacyclovir therapy starting from diagnosis of maternal infection until delivery, regardless of prenatal diagnosis of infection.