The diagnosis of fetal hydrocephalus prior to 22 weeks.

The prenatal diagnosis of hydrocephalus is described in 11 cases between 17 and 21 weeks using two sonographic criteria. These sonographic findings involve the asymmetrical appearance of the choroid plexus and the size and configuration of the anterior horns of the lateral ventricles. We have found that these criteria can accurately diagnose fetal hydrocephalus in the first half of the second trimester.