Omphalocele and gastrochisis.

Between January 1989 and November 1996 we detected a total of 44 cases of anterior abdominal wall defects comprising 29 with an omphalocele and 15 with gastrochisis. The gestational age at antenatal diagnosis of gastrochisis (mean = 17 weeks, 95% CI = 15-19) was significantly lower than for omphalocele (mean = 19.0 weeks, 95% CI = 17-21). Whereas gastrochisis tended to occur in relatively younger mothers (mean age = 23 years), omphalocele was associated with a comparatively advanced maternal age (mean age = 28 years). The sensitivity of ultrasound detection was the same for both malformations (omphalocele = 86.2%; gastrochisis = 86.7%). Additional structural anomalies were found in a higher proportion of those with an omphalocele compared with those with gastrochisis (62% vs. 20%). All the three cases of chromosomal anomalies were detected in omphalocele fetuses with an intracorporeal liver. Perinatal mortality was higher, albeit nonsignificantly, among fetuses with omphalocele.