Congenital Cytomegalovirus Infection in the Absence of Maternal Cytomegalovirus-IgM Antibodies

Background: Congenital cytomegalovirus (cCMV) infections are the most prevalent intrauterine infections worldwide and are the result of maternal primary or non-primary infections. Early maternal primary infections are thought to carry the highest risk of fetal developmental abnormalities as seen by ultrasound; however, non-primary infections may prove equally detrimental. Methods/Results: This case series presents 5 cases with fetal abnormalities detected in the second and third trimester, in which cCMV infection was ruled out due to negative maternal CMV-IgM. Discussion: This series highlights the possible pitfalls in serology interpretation and fetal diagnosis necessary for appropriate parental counseling. Once fetal abnormalities have been confirmed and cCMV is suspected, maternal CMV serostatus and fetal infection should be determined. Maternal CMV serology may be ambiguous; therefore, caution should be exercised when interpreting the results.