A normal second-trimester ultrasound does not exclude intracranial structural pathology.

OBJECTIVE

To report the prenatal diagnosis and management of 34 fetuses with various intracranial structural pathologies diagnosed following a normal second-trimester ultrasound examination.

METHODS

We retrospectively reviewed the images of 203 abnormal central nervous system ultrasound examinations performed between 13 and 37 weeks of gestation at our prenatal diagnosis unit. In 34 (16.7%) of them at least one previous second-trimester ultrasound examination had been performed and considered normal. These 34 fetuses represent the study group.

RESULTS

The following intracranial pathologies were diagnosed: dysgenesis of the corpus callosum, ventriculomegaly, cerebral cysts or hemorrhage, migrational disorders, vermian dysgenesis, arachnoid cysts, macrocephaly, enlarged subarachnoid space, brain calcifications and microcephaly.

CONCLUSION

A normal second-trimester ultrasound scan does not rule out significant intracranial anomalies. Parents and physicians should be informed about the limitations of second-trimester sonography as far as brain diagnosis is concerned. A repeat third-trimester scan may enable more accurate diagnosis and counseling.