Maternal characteristics
| Variables | n | n | Per cent |
|---|---|---|---|
| Sample size | 376 | ||
| Age at participation, years | |||
| Total, mean (SD) | 32.5 (4.4) | ||
| <25 | 19 | 5.05 | |
| 25–29 | 73 | 19.41 | |
| 30–34 | 157 | 41.76 | |
| ≥35 | 127 | 33.78 | |
| Body mass index before pregnancy, kg/m2 | 375 | 21.14 | |
| <18.5 | 55 | 14.67 | |
| 18.5–24.9 | 272 | 72.53 | |
| ≥25 | 38 | 10.13 | |
| Parity | 376 | ||
| 0 | 170 | 45.21 | |
| 1 | 143 | 38.03 | |
| 2 | 55 | 14.63 | |
| ≥3 | 8 | 2.13 | |
| Marital status | 376 | ||
| Married | 370 | 98.40 | |
| Unmarried | 3 | 0.80 | |
| Divorced/widowed | 3 | 0.80 | |
| Smoking habits | 376 | ||
| Never smoked | 293 | 77.93 | |
| Ex-smoker | 64 | 17.02 | |
| Smoker | 19 | 5.05 | |
| Passive smoking | 60 | 15.96 | |
| Infertility treatment | 376 | ||
| Yes | 39 | 10.37 | |