Adjusted rate differences for maternal and fetal outcomes (per 1000 deliveries) and number needed to treat for vaginal birth after cesarean delivery, by delivery type*
| Outcome | Adjusted rate difference | NNT |
|---|---|---|
| Point estimate (95% CI) | ||
| Attempted VBAC delivery† | ||
| Maternal | ||
| Uterine rupture | 7.42 (6.09 to 8.96) | 135 |
| Uterine rupture not including dehiscence | 2.69 (1.91 to 3.73) | 372 |
| PPH and blood transfusion | 2.93 (2.17 to 3.86) | 341 |
| Severe morbidity | 5.42 (4.29 to 6.72) | 184 |
| Restricted morbidity | 2.93 (2.00 to 3.95) | 342 |
| Neonatal | ||
| Death | 0.11 (0.00 to 0.37) | 9056 |
| Assisted ventilation | 6.84 (5.30 to 8.65) | 146 |
| Assisted ventilation excluding CPAP | 3.46 (2.56 to 4.49) | 289 |
| Seizures | 0.78 (0.39 to 1.32) | 1280 |
| Respiratory distress syndrome | −5.50 (−7.70 to −3.30) | −182 |
| Mortality and morbidity | 7.09 (5.50 to 8.83) | 141 |
| Restricted mortality and morbidity | 3.82 (2.89 to 4.92) | 262 |
| Successful VBAC† | ||
| Maternal | ||
| Uterine rupture | −0.63 (−0.96 to −0.18) | −1587 |
| Uterine rupture not including dehiscence | −0.03 (−0.23 to 0.33) | −33 535 |
| PPH and blood transfusion | 3.81 (2.75 to 5.11) | 263 |
| Severe morbidity | 1.81 (0.73 to 3.11) | 553 |
| Restricted morbidity | −2.00 (−2.56 to −1.25) | −501 |
| Neonatal | ||
| Assisted ventilation | 1.12 (−0.56 to 2.79) | 896 |
| Respiratory distress syndrome | −17.6 (−20.4 to −15.4) | −57 |
| Mortality and morbidity | 1.16 (−0.43 to 3.04) | 864 |
| After failed VBAC delivery† | ||
| Maternal | ||
| Uterine rupture | 15.1 (12.7 to 18.0) | 66 |
| Uterine rupture not including dehiscence | 5.27 (3.86 to 7.21) | 190 |
| PPH and blood transfusion | 2.15 (1.37 to 3.13) | 465 |
| Severe morbidity | 8.70 (7.06 to 10.6) | 115 |
| Restricted morbidity | 7.34 (5.81 to 9.06) | 136 |
| Neonatal | ||
| Death | 0.19 (0.02 to 0.61) | 5385 |
| Assisted ventilation | 12.3 (10.1 to 14.8) | 81 |
| Assisted ventilation excluding CPAP | 5.63 (4.34 to 7.20) | 178 |
| Seizures | 1.06 (0.55 to 1.81) | 940 |
| Respiratory distress syndrome | 6.60 (3.30 to 9.90) | 152 |
| Mortality and morbidity | 12.7 (10.4 to 15.2) | 79 |
| Restricted mortality and morbidity | 6.17 (4.78 to 7.81) | 162 |
Note: CI = confidence interval, CPAP = continuous positive airway pressure, NNT = number needed to treat, PPH = postpartum hemorrhage, VBAC = vaginal birth after cesarean.
↵* Selected maternal and neonatal outcomes after attempted vaginal birth among women with a single previous pregnancy that resulted in a cesarean, who subsequently delivered a singleton at 37 to 43 weeks gestation in the current pregnancy in Canada (excluding Quebec) from 2003 to 2014. See footnotes to Table 2 and Table 3 for components of maternal and neonatal morbidity.
↵† Women who delivered by elective repeat cesarean served as the reference group.