Number
OR (95% CI)
P
DR (%)
FPR (%)
Maternal age (≥ 35 years)
302
Unaffected pregnancies
298
Trisomy 21
4
2.45 (0.57-8.13)
0.124
25.0
12.0
Increased fetal NT (≥ 2.4mm)
133
121
12
58.6 (17.3-251)
<0.0001
75.0
4.9
Increased fetal NT (≥ 2.5mm)
126
115
11
65.3 (20.2-243)
68.8
4.6
Increased fetal NT (≥ P 95)
92
81
45.3 (14.2-168)
3.3
Posistive combined test
73
59
14
285 (60.1-2639)
87.5
2.4