Ultrasonographic characteristics, genetic features, and maternal and fetal outcomes in fetuses with omphalocele in China: a single tertiary center study

BACKGROUND: Patients with omphalocele, a midline abdominal wall defect at the umbilical cord base, have a low survival rate. However, the long-term outcomes of fetuses with prenatally diagnosed omphalocele have scarcely been studied. Therefore, we investigated the ultrasonographic features, genetic characteristics, and maternal and fetal outcomes of fetuses with omphalocele and provided a reference for the perinatal management of such cases. METHODS: A total of 120 pregnant females with fetal omphalocele were diagnosed using prenatal ultrasonography at the Fujian Provincial Maternity and Child Health Hospital from January 2015 to March 2022. Amniotic fluid or cord blood samples were drawn at different gestational weeks for routine karyotype analysis, chromosomal microarray analysis (CMA) detection, and whole exome sequencing (WES). The maternal and fetal outcomes were followed up. RESULTS: Among the 120 fetuses, 27 were diagnosed with isolated omphalocele and 93 with nonisolated omphalocele using prenatal ultrasonography. Cardiac anomalies were the most observed cause in 17 fetuses. Routine karyotyping and CMA were performed on 35 patients, and chromosomal abnormalities were observed in five patients, trisomy 18 in three, trisomy 13 in one, and chromosome 8–11 translocation in one patient; all were non-isolated omphalocele cases. Six nonisolated cases had normal CMA results and conventional karyotype tests, and further WES examination revealed one pathogenic variant and two suspected pathogenic variants. Of the 120 fetuses, 112 were successfully followed up. Eighty of the 112 patients requested pregnancy termination. Seven of the cases died in utero. A 72% 1-year survival rate was observed from the successful 25 live births. CONCLUSION: The prognosis of fetuses with nonisolated omphalocele varies greatly, and individualized analysis should be performed to determine fetal retention carefully. Routine karyotyping with CMA testing should be provided for fetuses with omphalocele. WES is an option if karyotype and CMA tests are normal. If the fetal karyotype is normal and no associated abnormalities are observed, fetuses with omphalocele could have a high survival rate, and most will have a good prognosis.