Rare chromosomal abnormalities: Can they be identified using conventional first trimester combined screening methods?

To evaluate the performance of first trimester combined screening for the detection of rare chromosomal abnormalities, other than Trisomies 21, 18 or 13 or 45 × .A database containing 36,254 pregnancies was analyzed. These patients were recruited at 15 US centers and included singleton pregnancies from 10 3/7-13 6/7 weeks. All patients had a nuchal translucency (NT) scan and those without a cystic hygroma (N = 36,120) underwent a combined first...