Prediction of an abnormal karyotype in fetuses with omphalocele

The aim of this study was to assess the value of ultrasonographic evaluation in predicting abnormal karyotypes in fetuses with omphalocele. Forty fetuses with antenatally diagnosed omphalocele and available karyotype results were reviewed. Ultrasound evaluation included herniation contents and size, and the detection of other anomalies. Nine of 40 consecutive fetuses had abnormal karyotypes: trisomy 18 (n = 5), trisomy 13 (n = 3), 47,XXX (n = 1). Only 1/25 with an extracorporeal liver versus 8/15 with an intracorporeal liver had abnormal chromosomes [P = 0.0006, RR = 0.14 (0.02 < RR < 0.9)]. Small defects (< 3 cm) were associated with abnormal karyotypes [P = 0.01, RR = 4.7 (1.4 < RR < 15.6)]. Finding concurrent malformations was highly associated with chromosomal anomalies [P = 0.00004, RR = 4.4 (2.3 < RR < 8.5)]. The presence of associated malformations, an intracorporeal liver, and a small herniation size are highly suggestive of an associated abnormal karyotype.