Pregnancies conceived using assisted reproductive technologies (ART) have low levels of pregnancy-associated plasma protein-A (PAPP-A) leading to a high rate of false-positive results in first trimester screening for Down syndrome

Abstract

Background: First trimester screening (FTS) for Down syndrome combines measurement of nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A (PAPP-A). The aim of this study was to undertake a detailed analysis of FTS results in singleton pregnancies conceived using assisted reproductive technologies (ART) and non-ART pregnancies. Methods: A record linkage study compared outcomes in 1739 ART-conceived and 50 253 naturally conceived pregnancies. Results: Overall, significantly lower PAPP-A levels were detected in ART pregnancies (0.83 multiples of median, MoM) than in controls (1.00 MoM) (t-test P < 0.001). This difference remained after excludin..