Table 1.
Clinical characteristics of all women in case and control groups
| Clinical characteristics | Case group (n = 141) | Control group (n = 166) | Statistical values | P |
|---|---|---|---|---|
| Maternal age (years) | 32.7 ± 4.7 | 34.6 ± 4.0 | −3.788* | <0.001 |
| BMI preconception (kg/m2) | 22.7 ± 3.5 | 23.3 ± 3.4 | −1.587* | 0.114 |
| BMI at delivery (kg/m2) | 27.1 ± 4.0 | 27.9 ± 4.0 | −1.754* | 0.080 |
| Gestational age (weeks) | 36.1 ± 5.3 | 37.9 ± 1.9 | −3.955* | <0.001 |
| Fetal birth weight (g) | 2689.2 ± 597.6 | 3197.4 ± 567.5 | −7.516* | <0.001 |
| Gravity | 2 (2–7) | 2 (2–8) | 2.777† | 0.005 |
| Parity | 1 (1–2) | 1 (1–5) | −2.184† | 0.029 |
| Induced abortion | 1 (0–4) | 1 (0–4) | 3.608† | <0.001 |
| Received ART | 3 (2.1) | 3 (1.8) | 0.041‡ | 0.840 |
| Other uterine surgery | 9 (6.4) | 10 (6.0) | 0.017‡ | 0.897 |
| Elective CS | 127 (90.1) | 116 (69.9) | 18.837‡ | <0.001 |
Data are shown as mean ± SD, median (range) or n (%). *t value; †Z value; ‡Chi-square value. ART: Assisted reproductive technology; CS: Cesarean section; SD: Standard deviation; BMI: Body mass index.