Table 1 Demographics characteristics of the 468 women under prenatal diagnosis with NIPT positive results in the laboratory
Characteristics | Cases | Constituent ratio |
|---|---|---|
Ethnicity (Chinese) | 468 | 100.0 |
Singleton pregnancy | 450 | 96.2 |
Pregnancy | Â | Â |
 History 1 | 121 | 25.9 |
 History 2 | 137 | 29.3 |
 History 3 | 101 | 21.6 |
 History ≥ 4 | 109 | 23.3 |
Parity nullipara | 182 | 38.9 |
 Primipara | 221 | 47.2 |
 Mutipara | 65 | 13.9 |
Results of serum screening | Â | Â |
 High risk | 71 | 15.2 |
 Moderate risk | 52 | 11.1 |
 Low risk | 56 | 12.0 |
 Not performed | 289 | 61.8 |
Advanced age women (AA ≥ 35) | 171 | 36.5 |
Ultrasound soft indications | 146 | 31.2 |
Ultrasonic structural abnormality | 59 | 12.6 |
Adverse pregnancy history | 28 | 6.0 |
Twin | 18 | 3.8 |
IVF-ET pregnancy | 21 | 4.5 |