The added value of detailed early anomaly scan in fetuses with increased nuchal translucency

Objective: This study aims to assess the utility of a detailed early fetal anatomy scan prior to karyotyping in the management of pregnancies with an increased nuchal translucency (NT). Methods: The study included fetuses with NT above the 99th centile. These women were offered the option of an early detailed fetal anatomy scan prior to genetic evaluation. The presence or absence of major sonographic findings was analyzed for its predictive value for fetal aneuploidy. Results: An increased NT >99th centile was detected in 43 fetuses (1.8%). Mean NT was 4.5 mm (range 3.4–9.0), and gestational age at the early fetal anatomy survey was 12.4 weeks (12–13.6). Major sonographic findings were present in 30 fetuses (69.8%); 24 of them underwent karyotyping, and it was abnormal in 14. Among the 13 fetuses without major sonographic findings, 12 had normal karyotype results, and 1 had aneuploidy, yielding a positive predictive value of 58.3% of early fetal anatomy scan for abnormal karyotype results. Multivariate logistic regression analysis showed that the presence of major sonographic findings was as an independent predictor of fetal aneuploidy (adjusted odds ratio 8.15). Conclusion: A detailed early anatomy scan upon detection of increased NT has an important value in the prediction of fetal aneuploidy.