Proportions of women receiving obstetric interventions during labour and delivery, 1999–2011
| Intervention | Non–First Nations mothers, no. (%) n = 206 841 | First Nations mothers, no. (%) n = 9152 | Risk difference (95% CI) | Adjusted* risk difference (95%CI) | Adjusted† risk difference (95%CI) |
|---|---|---|---|---|---|
| Pain management | |||||
| Nitrous oxide–oxygen | 97 920 (47.3) | 4 265 (46.6) | −0.7 (−1.8 to 0.3) | −0.2 (−1.4 to 1.0) | 2.1 (0.9 to 3.4) |
| Epidural | 90 819 (43.9) | 3 217 (35.2) | −8.8 (−9.8 to −7.8) | −5.2 (−6.3 to −4.0) | −2.8 (−4.1 to −1.6) |
| Labour induction‡ | 55 686 (26.9) | 1 791 (19.6) | −7.4 (−8.2 to −6.5) | −5.9 (−7.3 to −4.5) | −5.9 (−7.4 to −4.5) |
| Labour augmentation | |||||
| Artificial rupture of membranes | 60 635 (29.3) | 3 301 (36.1) | 6.8 (5.8 to 7.8) | 2.9 (1.9, 4.0) | 3.2 (2.0 to 4.3) |
| Oxytocin | 51 696 (25.0) | 1 829 (20.0) | −5.0 (−5.8 to −4.2) | −1.1 (−2.1 to 0.0) | 0.0 (−1.2 to 1.1) |
| Instrumental delivery | |||||
| Forceps | 15 699 (7.6) | 297 (3.2) | −4.3 (−4.7 to −4.0) | −2.7 (−3.3 to −2.2) | −2.2 (−2.9 to −1.5) |
| Vacuum | 24 471 (11.8) | 851 (9.3) | −2.5 (−3.1 to −1.9) | −1.4 (−2.1 to −0.6) | −1.6 (−2.4 to −0.9) |
| Cesarean delivery | |||||
| Any indication | 64 067 (31.0) | 2 145 (23.4) | −7.5 (−8.4 to −6.6) | −1.3 (−2.3 to −0.2) | −1.8 (−3.0 to −0.7) |
| For labour dystocia | 22 406 (10.8) | 819 (8.9) | −1.9 (−2.5 to −1.3) | −0.2 (−0.9 to 0.6) | −0.4 (−1.2 to 0.3) |
| For nonreassuring fetal monitoring | 13 428 (6.5) | 409 (4.5) | −2.0 (−2.5 to −1.6) | −1.0 (−1.5 to −0.4) | −0.7 (−1.4 to −0.1) |
| Elective | 8 998 (4.4) | 182 (2.0) | −2.4 (−2.7 to −2.1) | −1.1 (−1.6 to −0.6) | −1.1 (−1.6 to −0.6) |
Note: CI = confidence interval.
↵* Adjusted for maternal characteristics (maternal age, prepregnancy body mass index, pre-existing or gestational hypertension, pre-existing or gestational diabetes. Missing values for body mass index were imputed by use of predictive mean matching.
↵† Adjusted for distance.
↵‡ This model includes a statistical interaction term between age and First Nations status.