Characteristic | SP group | IVF group | p value |
---|---|---|---|
Maternal age | Â | Â | Â |
 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 | Â | Â | Â |
 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 | Â | Â | Â |
 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 | – |