Table 4 Comparison between different stratified pregnancy characteristics with the results of prenatal diagnostic validation
Characteristics | No.of patients(%) | NIPT Positive | Prenatal diagnostic validated | PPV(%) | P | |
|---|---|---|---|---|---|---|
TP | FP | |||||
Maternal age (years) | ||||||
  < 35 | 2605 (28.39) | 16 | 6 | 9 | 40.00 | 0.142 |
  ≥ 35 | 6571 (71.61) | 30 | 13 | 9 | 59.09 |  |
Gestational age at NIPT (weeks) | ||||||
 9–12+6 | 7913 (86.24) | 40 | 17 | 15 | 53.13 | 0.929 |
 13–14+6 | 634 (6.90) | 5 | 2 | 2 | 50.00 |  |
 15–19+6 | 601 (6.55) | 1 | 0 | 1 | 0.00 |  |
  ≥ 20 | 28 (0.31) | 0 | 0 | 0 | N/A |  |
BMI | ||||||
  < 18.5 | 738 (8.04) | 7 | 2 | 4 | 33.33 | 0.531 |
 18.5–22.9 | 5367 (58.49) | 22 | 10 | 8 | 55.56 |  |
 23.0–24.9 | 1463 (15.94) | 8 | 5 | 1 | 83.33 |  |
 25.0–29.9 | 1317(14.35) | 9 | 2 | 5 | 28.57 |  |
  ≥ 30 | 291 (3.17) | 0 | 0 | 0 | N/A |  |
Method of conception | ||||||
 Natural | 6773 (73.81) | 35 | 14 | 15 | 48.28 | 0.672 |
 IVF | 2403(26.19) | 11 | 5 | 3 | 62.50 |  |
Clinical indication | ||||||
 Advanced maternal age (age ≥ 35 years) | 6312 (68.79) | 30 | 13 | 11 | 54.17 | 0.147 |
 High or critical risk of serological screening | 80 (0.87) | 0 | 0 | 0 | N/A |  |
 Abnormal ultrasound screening | 136 (1.48) | 1 | 1 | 0 | 100.00 |  |
 Previous history | 95 (1.04) | 0 | 0 | 0 | N/A |  |
 Parental chromosomal aberration | 24 (0.26) | 2 | 0 | 0 | N/A |  |
 Voluntary demand | 2326 (25.35) | 13 | 5 | 7 | 41.67 |  |
 Others | 203 (2.21) | 0 | 0 | 0 | N/A |  |