Aim: The aim of this study was to evaluate the performance of the combined test (nuchal translucency, NT) and maternal serum free-beta human chorionic gonadotropin (free beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A), compared to the NT measurement alone, in fetal aneuploidy screening in the general population and in pregnant women aged 35 years and over. In addition, the association between increased NT and presence of cardiac defects in fetuses with normal karyotype was evaluated.
Methods: Screening at 11-14 weeks of gestation by NT measurement and combined test was carried out in 1521 pregnant women. The estimated risk for trisomy 21 and trisomy 13+18 was calculated (risk cut-off 1/300 and 1/750 respectively) and the outcomes was evaluated.
Results: Ten cases of trisomies (21 and 18) occurred, seven of which among the older group of pregnant women. The detection rate (DR) for the combined test was 80% in the general population and 85.7% in older pregnant women, which resulted higher rate than NT measurements alone. Detection rate of cardiac defects using NT measurements was 66.6%.
Conclusion: The combined test is an effective screening for aneuploidies and reduces at 14% the need of invasive testing in the older obstetric population, detecting all the trisomies occurred in this group. The association between increased NT and cardiac defects is confirmed but it seems too weak to consider NT as a single screening strategy for these abnormalities.