Integrated first- and second-trimester Down syndrome screening test among unaffected IVF pregnancies

Objective The aim of the current study was to assess the profile of markers that constitute the integrated test and to measure its false-positive rates (FPR) among a preselected group of unaffected IVF pregnancies. These results were compared with the reference laboratory values that reflect the general obstetric population, which underwent the same investigative protocol. Methods Ninety-nine unaffected singletons from IVF-pregnant women and 1781 controls, all evaluated by the same laboratory, underwent a nondisclosure integrated Down syndrome screening test. This test comprised first-trimester nuchal translucency (NT) and pregnancy-associated plasma protein-A (PAPP-A) assessment, followed by a midgestation quadruple test. Only upon completion of the integrated screening test, the parturient women were informed of its results. Results The mean maternal age of the study and the control group was 32.2 +/- 4 and 30.4 4 years respectively (t-test <0.005). The marker levels were expressed as multiples of the gestation-specific normal medians. The IVF group had lower PAPP-A (0.78 vs 1.03, t-test P < 0.05) and higher NT (1.14 vs 1.01, t-test P < 0.05) values, respectively. All the other markers were similar for both groups. On the basis of the integrated test, a higher rate of lVF pregnancies were defined as being screen-positive (6.1% vs 3.7%), although the values did not reach a level of statistical significance. Conclusions Since NT alone yielded the same FPR as the integrated test, the option of various sonographic screening combinations in this group warrants further investigation. Copyright (C) 2004 John Wiley Sons, Ltd.