Gastroschisis and exomphalos: precise diagnosis by midpregnancy ultrasound.

As part of a regional screening programme for neural-tube defects the cause of the raised alpha-fetoprotein levels was correctly identified in 13 pregnancies with a fetal abdominal wall defect by the 22nd week. Careful ultrasound study identified gastroschisis in seven fetuses and exomphalos in six: the presence or absence of a sac, the course of the umbilical vessels and the abdominal organs involved were the most important diagnostic criteria. Pregnancy continued into the third trimester in five cases complicated solely by gastroschisis and two babies have survived the neonatal period following surgical correction. It is suggested that precise identification by ultrasound of the type and severity of abdominal wall defect and also of the presence or absence of associated anomalies will enable the selection of some babies with gastroschisis or isolated exomphalos which have a good prognosis for survival without handicap.