The dynamic fetal brain

PURPOSE: To evaluate fetuses with normal intracranial anatomy in the second trimester that became abnormal in the third trimester. METHODS: We sonographically examined 6 fetuses with a normal second-trimester head sonogram that presented later in pregnancy with an abnormal head sonogram. RESULTS: Four categories of intracranial pathology were depicted: obstructive hydrocephalus, intraventricular intracranial hemorrhage, non-intraventricular intracranial hemorrhage, and porencephaly. CONCLUSIONS: Despite a normal midtrimester intracranial examination, evaluation of the fetal intracranial contents should be undertaken in subsequent sonographic examinations, because significant pathology can develop spontaneously.