Management of cytomegalovirus infection in pregnancy: is it time for valacyclovir?

Background: Congenital cytomegalovirus (CMV) infection is the leading infectious cause of neurological impairment for which, currently, there are no approved antenatal treatment options. Objectives: The aim of this article was to summarize the available evidence on the use of valacyclovir during pregnancy to prevent and treat congenital CMV infection and disease. Sources: Two databases (PubMed and ClinicalTrial.gov) were reviewed. Content: Six relevant documents were identified, namely one observational study, three clinical trials, two case reports. Most relevant findings were those from two clinical trials. A phase 2/3 placebo-controlled study showed a decrease of 71% (5 of 45 vs 14 of 47) in rate of CMV vertical transmission in women treated with 8 g/day valacyclovir following primary CMV infection in pregnancy. A phase 2, single-arm clinical trial, showed that 8 g/day valacyclovir administered to mothers of symptomatic infected foetuses increased the portion of asymptomatic neonates to 82% (34 of 41), compared with 43% (20 of 47) in untreated pregnancies from a historical cohort. Implications: Studies in favour of using valacyclovir during pregnancy for prevention and treatment of congenital CMV infection are emerging but are still few. Randomized clinical trials on large cohorts of patients investigating the efficacy on prevention and treatment of congenital CMV are required. Unfortunately, this will be probably not be feasible at least in the short period. In the meantime, data on the ‘off label’ use of valacyclovir for CMV in pregnancy could be collected within a multicentre observational study.