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. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007