Demographic and obstetric data
| Characteristics | Mean (SD) and range/n (%) |
| Age (years)† | 32.0 (5.2) 18.0–50.0 |
| Gestation at booking visit (weeks) | 17.0 (6.2) 1.0–39.0 |
| Weight at booking visit (kg) | 75.0 (20.2) 35.0–158.0 |
| BMI at booking visit (kg/m²) | 28.0 (7.0) 15.8–62.3 |
| Gestation at delivery (weeks) | 38.0 (2.1) 25.0–42.0 |
| BMI at caesarean section (kg/m²) | 32.0 (6.9) 17.0–66.2 |
| Difference in BMI between delivery and booking visit (kg/m2) | 4.0 (2.7) −3.6–16.9 |
| Comorbidities | |
| Previous caesarean section | 638 (43.8%) |
| Multiple pregnancy | 68 (4.7%) |
| Pre-eclampsia | 62 (4.3%) |
| Classification of urgency of caesarean section* | |
| Category 1 | 116 (8.0%) |
| Category 2 | 433 (29.7%) |
| Category 3 | 261 (17.9%) |
| Category 4 | 647 (44.4%) |
| Maternal and neonatal outcomes | |
| Mother admitted to intensive care unit | 11 (0.7%) |
| Mother received red cell transfusion | 20 (1.4%) |
| Mother returned to the operating room | 9 (0.6%) |
| Neonate admitted to neonatal intensive care unit | 60 (4.1%) |
| Neonate admitted to special care unit | 227 (15.6%) |
*Royal College of Obstetricians and Gynaecologists (RCOG) classification.
†Age at delivery.
‡Sample from 1505 participants excluding those missing data on duration of anaesthesia (n=1; 0.1%), BMI (n=45; 3.0%) and potential confounders: age (n=1; 0.1%), gestation at delivery (no missing), multiple pregnancy (n=1; 0.1%), pre-eclampsia (no missing), caesarean section urgency (n=3; 0.2%) and previous caesarean section (no missing); n=1457.
BMI, body mass index.