First trimester diagnosis of fetal nuchal edema. Report of 29 cases.

During a 4-year period, 29 fetal nuchal edemas were observed, associated with other ultrasound abnormalities in 7 cases (24%). Fetal karyotypes were abnormal in 10 cases: 6 trisomy 21; 3 trisomy 18, and 1 Turner's syndrome. Isolated fetal nuchal edema was associated with aneuploidy in 4 cases: 3 trisomy 21, and 1 trisomy 18. The average age of the women carrying a fetus with nuchal edema associated or not with a trisomy 21 was 38.3 and 30.8 years, respectively. These results are similar to those found in the literature. It would appear that maternal age is a better marker in trisomy 21 screening than isolated fetal nuchal edema.