Diagnosis and management of fetal holoprosencephaly.

The holoprosencephalies are a spectrum of cerebral and facial malformations resulting from incomplete division of the embryonic forebrain. Using ultrasound to search for structural defects in the fetal brain and to measure interorbital distances, the alobar variety can be diagnosed antenatally. A series of seven cases is presented. Criteria for diagnosis and guidelines for obstetric management are presented.