OUTCOME OF FETUSES WITH ENLARGED NUCHAL TRANSLUCENCY AND NORMAL KARYOTYPE

The aim of this study was to examine the relationship between nuchal t ranslucency measurements and outcome of pregnancy with special regard to fetuses with an enlarged nuchal translucency and a normal Karyotype . Fetal nuchal translucency measurements were performed on consecutive mothers attending the prenatal diagnosis center of our hospital. A co mplete follow-up was obtained in 88.4% of the cases. Of the 74 fetuses (4.4%) with an enlarged nuchal translucency (greater than or equal to 3 mm), 25 (33.8%) had an abnormal Karyotype. Two pregnancies ended in a spontaneous abortion before Karyotyping was performed. In the remai ning 47 eukaryotic fetuses with enlarged nuchal translucency, five (10 .6%) had a structural anomaly, two were affected by genetic syndromes (4.2%) and an additional four fetuses (8.5%) were affected by a single -gene disorder. A spontaneous abortion or an intrauterine death occurr ed in 6.4% and in 2.1% of these fetuses, respectively. The total incid ence of an unfavorable outcome in the group of chromosomally normal fe tuses with enlarged nuchal translucency was 32%. In contrast, in the g roup with a normal nuchal translucency (< 3 mm), the incidence of an u nfavorable outcome was 7.5%. There is a strong association between enl arged nuchal translucency measurements and congenital (structural and genetic) abnormalities, as assessed by receiver operator characteristi c analysis. This may represent, in fetuses with a normal karyotype, a non-specific sign of a disturbance in the developmental process. In th ese cases, detailed ultrasound surveillance is recommended.