PAPPA and trisomy 21: The woman subsequently attended the first trimester screening at GA 12 + 5 where the nuchal translucencies were 1.2 and 1.3 mm, PAPP-A 0.514 MoM and fβ-hCG 0.34 MoM, which gave combined risks for trisomy 21 of 1:1,077 and 1:917, respectively.