The specificity of the HCMV IgM assay is not sufficient for a precise diagnosis of maternal HCMV infection because IgM can persist for a long time in some patients.16 Additionally, the reliability of the IgG avidity assay for distinguishing between recent and past infections remains unclear.17–19 Because of the low frequency of HCMV infection in FGR cases, in addition to reliable serological examinations, pathological analysis of placental tissue should be performed in more cases to determine the precise clinical features of HCMV-related FGR. Here, CD40LG is linked to infection.