Maternal and infant characteristics
| Child age range at interview | Maternal age at birth (years) | Gestational age (weeks) | Siblings | Neonatal Intensive Care Unit stay | Delivery type | |
| 1 | >28 to <30 months | >38 to <40 years | 33.6 | 2 (older) | No | Vaginal |
| 2 | >22 to <24 months | >34 to <36 years | 34.4 | 0 | Yes | Caesarean |
| 3 | >20 to <22 months | Withheld | 34.4 | 0 | Yes | Vaginal |
| 4 | >34 to <36 months | >26 to <28 years | 34.7 | 0 | Yes | Caesarean |
| 5 | >22 to <24 months | >28 to <30 years | 32 | 0 | Yes | Caesarean |
| 6 | >20 to <22 months | >30 to <32 years | 36.3 | 1 (older) | Yes | Vaginal |