Association of congenital cytomegalovirus (CMV) infection with autism spectral disorder (ASD) has been suggested since 1980s. Despite the observed association, its role as a risk factor for ASD remains to be defined. In the present review, we systematically evaluated the available evidence associating congenital CMV infection with ASD using PubMed, Web of Science, Cochrane Library, and Embase databases. Any studies on children with CMV infection and ASD were evaluated for eligibility and three observational studies were included in meta-analysis. Although a high prevalence of congenital CMV infection in ASD cases (OR 11.31, 95% CI 3.07–41.66) was indicated, too few events (0–2 events) in all included studies imposed serious limitations. There is urgent need for further studies to clarify this issue.
