The natural history of euploid pregnancies with first-trimester cystic hygromas****

OBJECTIVES: Little information is available with regard to prognosis of euploid fetuses with first-trimester nuchal hygromas. To evaluate this population, the natural history, pregnancy outcome, and pediatric implication of this lesion were determined. STUDY DESIGN: Fetuses with cystic hygromas detected in the first trimester were retrospectively identified, and karyotype results were documented. Pregnancy outcome of those fetuses having a euploid karyotype was obtained, and physical examination of the live-born neonates and infants was performed by a clinical geneticist. RESULTS: A normal karyotype was identified in 22 (51%) of these pregnancies. Eighty-two percent of the euploid pregnancies were continued, with 89% of the fetuses surviving to the third trimester. Dysmorphic sequelae were documented in three children, including Noonan syndrome in one. CONCLUSION: In the presence of a normal karyotype fetuses with a first-trimester nuchal hygroma have an excellent prognosis. Normal outcome was seen in 80% of pregnanCies carried to the third trimester.