Etiologic heterogeneity of fetal hydrocephalus diagnosed by ultrasound.

Increased use of fetal ultrasound imaging by obstetricians has led to an increased rate of in utero detection of fetal malformations. Eight patients referred for level II sonography for confirmation of suspected fetal hydrocephalus were found to have affected fetuses. Examination of the resulting fetuses and infants revealed remarkable etiologic heterogeneity for the hydrocephalus. The risk for recurrence of hydrocephalus and other malformations in future offspring of these mothers varies from negligible to 25%. This experience emphasizes that there are many causes of fetal hydrocephalus and that careful diagnostic studies must be performed on any fetus or infant found to have hydrocephalus, so that accurate genetic counseling can be provided to the family.