Background: Human cytomegalovirus (HCMV) infection is the most common congenital infection in developed countries. Recent studies highlighted similar percentages of symptoms in HCMV congenitally-infected infants following either primary or non-primary maternal infections.

Objectives: To highlight correlation between neonatal brain abnormalities, detected by ultrasounds and magnetic resonance image in HCMV congenitally-infected infants, and maternal virological parameters during pregnancy, especially in seroimmune mothers.

Study design: We considered the 36 HCMV congenitally-infected infants (26 asymptomatic and 10 symptomatic) referred to our center over 4 consecutive years. Maternal serologic data during pregnancy were available for all cases. Neonatal cranial ultrasound and magnetic resonance images were related to maternal virological findings during pregnancy.

Results: Polymicrogyria was observed in 6/10 (60.0%) symptomatic and 0/26 (0%) asymptomatic newborns (p < 0.001). The 6 infants with polymicrogyria were all born to mothers who were HCMV IgG reactive with negative specific IgM, in the first trimester of pregnancy (range: 8-14 weeks). For these six women, pre-conceptional HCMV serologic information were absent and they all were considered immune for HCMV during pregnancy, therefore no further serologic investigation or specific educational and hygienic information were recommended during gestation.

Conclusion: These data highlight the elevated frequency of polymicrogyria in HCMV congenitally-infected infants born to mothers defined as seroimmune in the early stage of pregnancy and having no pre-existing serologic information. The paper stresses the potential utility of pre-conceptional screening to define maternal infection reliably (primary vs non-primary), and allow evidence-based counseling in women with positive serology, suggesting also preventive hygienic measures during pregnancy.