Table 1: Characteristic of the study population.
| Characteristic | n = 201 |
| Age (years, mean (range)) | 32.36 (18-47) |
| BMI (mean (range)) | 24.70 (18.05-47.40) |
| Abortion (n (%)) | 60 (29.9) |
| Nulliparous (n (%)) | 125 (61.7) |
| Multiparous (n (%)) | 76 (38.3) |
| - Primiparous (n (%)) | 48 (24.1) |
| - Second (n (%)) | 23 (11.7) |
| - Third (n (%)) | 2 (1.0) |
| - Fourth and more (n (%)) | 3 (1.5) |
| Gestational age (weeks, mean (range)) | 40.29 (37-42) |