PAPPA and trisomy 21: The combined first-trimester screening revealed a low risk for trisomy 21, 18, and 13 (PAPP-A 0.43 MoM; BhCG 1.19 MoM); risk for trisomy 21 1:1519, risk for trisomy 18 < 1:20000 and risk for trisomy 13 1:2275.