Fetal omphalocele: associated malformations and chromosomal defects.

Fetal karyotyping was performed in 35 cases of omphalocele diagnosed by ultrasonography at 16-36 weeks' gestation. Nineteen fetuses (54%) had chromosomal abnormalities; 17 had trisomy 18, one triploidy, and one Klinefelter's syndrome. Twenty-six (74%) of the fetuses were male. Detailed ultrasound examination of the fetuses revealed an additional malformation in 73% of the cases; the most frequent was congenital heart disease (47%). Twenty-two pregnancies were aborted electively, four resulted in intrauterine or neonatal death, and nine infants are alive. These findings contrast with the low rates of associated defects and high survival rates reported in the pediatric literature.