Table 1.

Evaluation and compare the incidence of chromosomal abnormalities based on final risk and NT percentile

Group characteristics	NT ≥99% (117) P: 0.002	NT <99% (17) 1/10≤ risk P: 0.003	NT<99% (119) 1/50≤ risk <1/10 P: 0.03	NT <99% (119) 1/100≤ risk <1/50 P: 0.36	NT <99% (254) 1/250≤ risk <1/100 P: 0.16	NT <99% (131) 1/250> risk P: 0.1
Normal	104 (88.88%)	12 (76.5%)	103 (84.9%)	115 (95.8%)	241 (93.8%)	136 (93.9%)
Numeric	12 (10.3%)	4 (23.5%)	9 (7.6%)	2 (1.7%)	4 (1.7%)	1 (0.8%)
Down syndrome	12	3	8	2	2	0
Others	0	1	1	0	2	1
De novo structural	1 (0.9%)	1 (5.9%)	6 (5%)	2 (1.7%)	7 (2.9%)	6 (46%)
Numeric cumulative	12 (37.5%)	16 (50%)	25 (78.125%)	27 (84.375%)	31 (96.875%)	32 (100%)
Structural cumulative	1 (43.47%)	2 (8.695%)	8 (34.782%)	10 (43.478%)	17 (73.913%)	23 (100%)
Total cumulative	13 (23.63%)	18 (32.72%)	33 (60%)	37 (67.27%)	48 (87.27%)	55 (100%)