The clinical course and outcome of hydrocephalus diagnosed in utero is not well understood. To approach this problem 40 cases were reviewed of intrauterine fetal hydrocephalus diagnosed with sonography, and follow-up information was obtained regarding them. Sonograms were evaluated for cerebral dimensions, biparietal diameter, brain mantle size, ventricular ratio, amount of amniotic fluid, and associated abnormalities. Neonatal brain sonograms and computed tomographic (CT) scans were reviewed also. Clinical charts were reviewed for maternal age and parity, referral source, family history, fetal age at diagnosis and delivery, mode of delivery, physical examination and/or autopsy findings, karyotype, amniotic alpha 1 fetoprotein level, cause of death, shunt placement after birth, and status of live infants. The observations indicate that the prognosis for fetal hydrocephalus is poor. Only six infants (15%) were alive after an average follow-up of 13 months. Three children were normal and the other three had...