FETAL-OUTCOME IN NUCHAL TRANSLUCENCY WITH EMPHASIS ON NORMAL FETAL KARYOTYPE

The aim of this study was to evaluate fetal outcome in fetuses with a nuchal translucency thickness of 3 mm or more, with emphasis on those with a normal karyotype. Between 1991 and 1994, a total of 104 pregnan cies with suspected ultrasound abnormalities were referred to our pren atal unit for a fetal anomaly scan before 16 weeks of gestation. Of th ese 104 pregnancies, 54 were referred because of a nuchal translucency thickness of 3 mm or more. Data on these 54 pregnancies will be prese nted. Karyotyping was performed in all cases. An abnormal karyotype wa s found in 26/54 (48 per cent) pregnancies. A normal karyotype was est ablished in the remaining 28 pregnancies. In this subset, five associa ted structural anomalies were detected at the first anomaly scan (9-15 weeks). Two pregnancies were terminated because of isolated nuchal tr anslucency. In four of the continuing 21 pregnancies, additional struc tural anomalies were detected only at the second anomaly scan (16-20 w eeks). Two of these were terminated because of bilateral renal dysplas ia and a combination of exomphalos and ectopia cordis. Finally, 19 pre gnancies progressed uneventfully and resulted in spontaneous delivery at a median gestational age of 40 weeks. A statistically significant d ifference in mean nuchal translucency thickness was found between case s with and without associated structural anomalies. This relationship indicates a more pronounced nuchal translucency thickness to be associ ated with a higher incidence of additional structural anomalies and, a s a result, a poorer fetal outcome.