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

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.

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.

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.

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.