Table 3.
Predictive factors for intrapartum caesarean section among women with a trial of labour for a planned vaginal birth, NSW, 2007–2011. Two models were fitted progressively adjusting for case-mix and hospital factors
| Variable and categories | Case-mix model | Hospital model |
|---|---|---|
| OR (95 % CI) | OR (95 % CI) | |
| Maternal age (years) | 1.02 (1.01, 1.03) | 1.02 (1.02, 1.03) |
| Country of birth | ||
| Australia or New Zealand | 1.00 | 1.00 |
| Europe or North America | 0.86 (0.74, 1.00) | 0.86 (0.74, 1.00) |
| Other | 1.17 (1.06, 1.29) | 1.17 (1.06, 1.29) |
| Smoking | 1.15 (1.03, 1.29) | 1.14 (1.02, 1.29) |
| Diabetes (pre-existing or gestational) | 1.27 (1.10, 1.46) | 1.27 (1.10, 1.46) |
| Hypertensive disorders | 1.31 (1.12, 1.53) | 1.31 (1.12, 1.53) |
| Other chronic medical conditionsa | 1.95 (1.38, 2.73) | 1.93 (1.37, 2.71) |
| Parity 2 or more (versus parity 1) | 0.70 (0.63, 0.78) | 0.70 (0.63, 0.78) |
| Labour/vaginal birth prior to index caesarean | 0.48 (0.42, 0.56) | 0.48 (0.42, 0.55) |
| Previous vaginal birth after caesarean | 0.16 (0.14, 0.19) | 0.16 (0.14, 0.19) |
| Previous perinatal death | 1.80 (1.32, 2.46) | 1.79 (1.31, 2.44) |
| Non-CS uterine scar | 2.78 (1.41, 5.48) | 2.75 (1.39, 5.44) |
| Assisted reproductive technology use (last 12 months) | 0.55 (0.44, 0.68) | 0.55 (0.45, 0.68) |
| Inter-pregnancy interval (months) | ||
| 0-17 | 0.92 (0.85, 1.00) | 0.92 (0.85, 1.00) |
| 18-59 | 1.00 | 1.00 |
| 60+ | 1.22 (1.06, 1.40) | 1.21 (1.06, 1.40) |
| Unknown | 0.83 (0.74, 0.92) | 0.82 (0.74, 0.92) |
| Placental conditionsb | 4.26 (3.22, 5.65) | 4.26 (3.22, 5.65) |
| Estimated gestational age (weeks) | ||
| 37 | 1.58 (1.37, 1.82) | 1.58 (1.38, 1.82) |
| 38 | 1.30 (1.18, 1.44) | 1.30 (1.18, 1.45) |
| 39 | 1.00 | 1.00 |
| 40 | 0.94 (0.86, 1.03) | 0.94 (0.86, 1.03) |
| 41+ | 1.41 (1.26, 1.58) | 1.41 (1.26, 1.57) |
| Large for gestational age (>90th percentile) | 1.71 (1.53, 1.90) | 1.71 (1.53, 1.91) |
| Stillbirth | 0.26 (0.11, 0.62) | 0.25 (0.10, 0.62) |
| Repeat caesarean rate after nulliparous breech caesarean (Propensity towards vaginal birth after caesarean section) | - | 1.04 (1.02, 1.07) |
| Instrumental delivery rate | - | 0.82 (0.71, 0.93) |
aIncluded renal, cardiac, asthma/COPD, autoimmune, thyroid and inflammatory bowel disease
bIncluded morbidly adherent placenta, placental abruption, placenta praevia, antepartum haemorrhage