Adverse outcomes after planned CDMR and planned vaginal delivery among women with low-risk singleton pregnancies resulting in a live or intrapartum stillbirth delivery in Ontario, Canada, between 2012 and 2018 (n = 422 210)
| AOI component | No. (%) of planned CDMR* n = 1827 | No. (%) of planned vaginal delivery* n = 420 383 | Planned CDMR v. planned vaginal delivery* | |
|---|---|---|---|---|
| Crude RR* (95% CI) | Adjusted RR† (95% CI) | |||
| Maternal component | ||||
| Maternal death | 0 (0.0) | 14 (0.0) | — | — |
| Uterine rupture | 0 (0.0) | 100 (0.0) | — | — |
| Maternal intensive care unit admission | S | 446 (0.1) | S | S |
| Unanticipated operative procedure | 21 (1.2) | 2212 (0.5) | 2.18 (1.42 to 3.35) | 2.00 (1.30 to 3.08) |
| Blood transfusion | 19 (1.0) | 3057 (0.7) | 1.43 (0.91 to 2.24) | 1.46 (0.93 to 2.30) |
| 3rd or 4th degree perineal tear | 0 (0.0) | 13 686 (3.3) | ||
| Any maternal components | 37 (2.0) | 18 336 (4.4) | 0.46 (0.34 to 0.64) | 0.41 (0.30 to 0.57) |
| Fetal or neonatal components | ||||
| Intrapartum or in-hospital newborn death with birth weight ≥ 2500 g, with no congenital anomalies | 0 (0.0) | 301 (0.1) | — | — |
| Birth trauma, ≥ 2000 g | 0 (0.0) | 2439 (0.6) | — | — |
| NICU admission > 2 d or transfer within 24 h of birth to a facility with a NICU for an infant ≥ 2500 g | 30 (1.6) | 12 479 (3.0) | 0.55 (0.39 to 0.79) | 0.52 (0.36 to 0.74) |
| 5-minute Apgar score < 7 | S | 5353 (1.3) | S | S |
| Any neonatal component | 34 (1.9) | 17 899 (4.3) | 0.44 (0.31 to 0.61) | 0.42 (0.30 to 0.58) |
| Any AOI component | 70 (3.8) | 34 999 (8.3) | 0.46 (0.37 to 0.58) | 0.42 (0.33 to 0.54) |
Note: AOI = Adverse Outcome Index, BMI = body mass index, CDMR = cesarean delivery on maternal request, CI = confidence interval, NICU = neonatal intensive care unit, RR = relative risk.
↵* Numbers are suppressed (S) for small cell sizes (n < 6).
↵† Adjusted for gestational age, maternal age, pre-pregnancy BMI, neighbourhood education quintile, maternal race, parity, conception type, anxiety, maternal substance use during pregnancy (includes self-reported alcohol, smoking and drug use during pregnancy), antenatal health care provider and maternal hospital level of care. C-statistic: 0.643.