In utero treatment of congenital cytomegalovirus infection with valganciclovir: an observational study on safety and effectiveness.

Background: The treatment of congenital cytomegalovirus (CMV) infection is usually administered to neonates after birth; however, it can be anticipated during the prenatal period by treating pregnant women in order to reduce the severity of the congenital disease. The most commonly used treatment for CMV during pregnancy is valaciclovir; however, valganciclovir has a higher potency against CMV and is the first choice for neonates with congenital CMV disease.

Objectives: We investigated neonatal and maternal safety of tertiary prevention in infected fetuses showing ultrasound features of infection using valganciclovir.

Methods: Retrospective cohort study of pregnant women and their symptomatic infected fetuses taking valganciclovir, 3 × 450 mg per day. All fetuses presented at least one prenatal feature on ultrasound. We assessed fetal/neonatal and maternal safety, as well as neonatal efficacy of treatment. The main outcome was neutropenia. Secondary outcomes included other haematological side effects, symptoms at birth and neonatal CMV-PCR was positive.

Results: Seventeen women with singleton pregnancies received valganciclovir from a median (IQR) of 27.1 (26.0-30.3) to 11.6 (6.5-12.9) weeks of gestation. No neonatal neutropenia was reported. One pregnancy was terminated for severe features. Three newborns (18%) were asymptomatic at birth, including one with negative CMV-PCR from blood and saliva. CMV-PCR was positive for 12/13 symptomatic newborns, with a median (IQR) log10 viral load of 3.36 (3.30-4.20), 4.03 (1.75-4.27) and 3.04 (0.00-3.40) log10 copies/mL in blood, urine and saliva, respectively.

Conclusions: Tertiary prevention by valganciclovir appears to be well tolerated for both fetus and mother. However, more extensive trials accompanied by long-term follow-up are needed.