Chromosomal anomalies in newborns with omphalocele

Omphalocele is the most common congenital abdominal wall defect; its reported incidence is 1 in 4,000 to 5,000 live births. With large defects, the liver is a median organ and lies within the sac (extracorporeal liver [ECL]). With small defects, only bowel or stomach is found outside the abdominal cavity (intracorporeal liver [ICL]). The goal of this study was to determine whether a relationship exists between the sac contents or the timing of diagnosis and the incidence of chromosomal abnormalities or survival among fetuses and newborns with omphalocele. From 1985 to 1995, 83 cases of omphalocele were managed at the authors' institution. In 50 cases the diagnosis was made using prenatal ultrasonography. All patients underwent fetal cardiac echography and amniocentesis. Twenty-four pregnancies were terminated electively because of severe associated anomalies. Of the 59 live births, 41 patients (69%) survived. The incidences of cardiac, chromosomal, and other anomalies were 24% (14), 10% (6), and 21% (16), respectively. Omphalocele with ICL is associated with a better survival rate than omphalocele with ECL (82% v 48%; P < .01) despite the significantly higher rate of karyotype abnormalities (16% v 0%; P < .05). The prognosis was poorer for patients with prenatally diagnosed omphalocele than for those with a postnatal diagnosis (mortality rate, 42% v 21%) because the former group had a higher percentage (70% v 9%) of ECL. Although the incidence of cardiac anomalies was similar for the ECL and ICL groups (33% v 18%), the former had more complex malformations. Death usually occurred in newborns who had neonatal respiratory distress owing to prematurity, or in those with chromosomal or cardiac anomalies. Chromosomal anomalies occurred mainly in cases of small omphaloceles that contained gut only, and it was the major cause of death among this group. In ECL cases, survival was primarily affected by the associated complex cardiac anomalies.