Which ultrasound finding is not characteristic of congenital CMV?

Congenital cytomegalovirus (CMV) infection is known for specific ultrasound findings that can indicate its presence in a fetus. Among these, cerebral ventriculomegaly, fetal hydrops, and microcephaly are commonly associated with congenital CMV.

Cerebral ventriculomegaly occurs due to increased cerebral fluid volume, which can result from the infection's impact on the developing brain. Microcephaly is another classic feature, reflecting impaired brain growth due to infection during gestation. Fetal hydrops, which presents as an abnormal buildup of fluid in two or more fetal compartments, can also occur as a severe manifestation of congenital CMV.

In contrast, cardiac malformations are not a specific characteristic of congenital CMV infection. While other congenital infections like rubella are more closely associated with cardiac anomalies, CMV does not have a direct correlation with cardiac malformations as a characteristic ultrasound finding. Thus, the correct answer focuses on the distinction between the hallmark signs of congenital CMV and other conditions where cardiac defects are more prevalent.