Table 1 Demographic and pregnancy characteristics of NIPT-screened pregnant women

Maternal age

 Age range (years)

18–48

21–48

–

 Older parturient women (≥ 35 years, n, %)

16,977 (18.60%)

793 (22.81%)

< 0.05

 ≤ 29 years (n, %)

41,154 (45.09%)

1234 (35.49%)

< 0.05

 30–34 years (n, %)

33,149 (36.32%)

1450 (41.70%)

< 0.05

 35–39 years (n, %)

15,692 (17.19%)

640 (18.41%)

0.06

 ≥ 40 years (n, %)

1285 (1.41%)

153 (4.40%))

< 0.05

 Average age (SD, years)

30.16 (4.60)

31.23 (4.23)

< 0.05

Gestational age

 Gestational age range (weeks)

12⁺⁰–26⁺⁶

12⁺⁰–25⁺⁴

–

 12⁺⁰–15⁺⁶ weeks (n, %)

12,204 (13.37%)

1337 (38.45%)

< 0.05

 16⁺⁰–19⁺⁶ weeks (n, %)

75,103 (82.28%)

2026 (58.27%)

< 0.05

 20⁺⁰–23⁺⁶ weeks (n, %)

3014 (3.30%)

94 (2.70%)

0.05

 24⁺⁰–26⁺⁶ weeks (n, %)

959 (1.05%)

20 (0.58%)

< 0.05

 Mean gestational age (weeks)

16⁺⁴

16⁺⁵

–

Type of pregnancy

 Singleton (n, %)

90,059 (98.66%)

2909 (83.66%)

< 0.05

 Twin (n, %)

1221 (1.34%)

568 (16.34%)

< 0.05

 Body mass index (BMI, kg/m²)

 BMI range (kg/m²)

14.01–57.10

21.32–37.50

–

 BMI average value (SD, kg/m²)

23.52 (3.73)

24.14 (3.55)

0.48

Total (n)

91,280

3477

–