Fetal hydrocephalus: sonographic detection and clinical significance of associated anomalies.

Sixty-one cases of fetal hydrocephalus were reviewed to determine the accuracy and clinical significance of prenatal ultrasound (US) for detecting concurrent anomalies. Of 61 fetuses studied, 51 (84%) had one or more major central nervous system (CNS) malformations (38 fetuses with 39 anomalies) and/or extra-CNS anomalies (34 fetuses). Only ten (16%) fetuses had no concurrent anomaly. Anomalies of the CNS were correctly identified with US in 35 of 39 (90%) cases. Of 34 fetuses (56%) with extra-CNS anomalies, 27 had multiple anomalies. One or more extra-CNS abnormality was identified with US in 22 of the 27 (81%) fetuses with multiple anomalies but no anomalies were identified with US in the seven patients with an isolated anomaly. Fetal mortality was directly related to the presence of extra-CNS anomalies (P less than .01). Many important anomalies coexisting with fetal hydrocephalus can be identified with US. Furthermore, sonographic detection of extra-CNS malformations carries a poor prognosis and was associated with a uniformly fatal outcome in this series.