Screening for fetal abdominal wall defects.

Failure of the lateral ventral folds to close by the third month of embryonic life results in an omphalocele. Although the abdominal wall defect is easily closed, the survival rate for infants with an omphalocele remains only 79%, largely the result of coexistent anomalies and chromosomal abnormalities. Gastroschisis is a deformation caused by disruption of the right omphalomesenteric artery and a resultant full-thickness defect in the abdominal wall. As a result, small bowel and, on occasion, even large bowel herniate into the amniotic space. Despite evidence of increased bowel irritability manifested by echogenic bowel wall thickening in fetuses with gastroschisis, the survival rate of more than 95% is largely the result of the lack of other severe anomalies associated with this defect. In addition, recent evidence suggests that the improvement in survival rate is also the result of improved perinatal care. The ability of perinatal specialists to categorize the defect along with associated anomalies and improved counseling regarding neonatal outcome have measurably increased the ability of families to assess the reproductive consequences and make informed decisions. This article outlines methods to identify patients at risk for having a fetus with an abdominal wall defect along with sonographic techniques to diagnose the majority of cases. Prompt consultation with individuals skilled in evaluating such defects ensures that appropriate perinatal care is provided.