Table 1.
Maternal characteristics for the study cohort used to investigate length of gestation and risk of prolonged pregnancy by maternal BMI category
| Study sample descriptives (n = 20 599) | |
|---|---|
| Age (years) mean (SD) | 28.6 (6.1) |
| Height (m) mean (SD) | 1.64 (0.7) |
| Weight (kg) median (IQR) | 65 (58–75) |
| Gestational age (days) median (IQR) | 283 (276–289) |
| BMI, n (%) | |
| Underweight | 2145 (10.4) |
| Normal | 9837 (47.8) |
| Overweight | 5470 (26.6) |
| Obese | 2112 (10.3) |
| Very obese | 723 (3.5) |
| Morbidly obese | 312 (1.5) |
| Race, n (%) | |
| White | 17 836 (86.6) |
| Black | 658 (3.2) |
| Asian | 592 (2.9) |
| Other | 891 (4.3) |
| Unknown | 622 (3.0) |
| Parity, n (%) | |
| Primiparous | 11 530 (56.0) |
| One previous pregnancy | 5627 (27.3) |
| More than one previous pregnancy | 3437 (16.7) |
| Unknown | 5 (0.01) |
| Smoking status, n (%) | |
| Non-smoker | 12 540 (60.9) |
| Stopped since pregnant | 2370 (11.5) |
| Smoker (>1 per day) | 5689 (27.6) |
| Hypertension, n (%) | 642 (3.1) |
| Diabetes mellitus, n (%) | 45 (0.2) |