Selected characteristics of the study cohort, for records included in the final analysis
| Characteristic | Quintile of regional FP delivery rate; % of cases* | |||||
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | All | |
| Delivery provider | ||||||
| FP (instrumental variable) | 4.2 | 9.0 | 16.3 | 38.9 | 67.7 | 27.3 |
| Obstetrician | 95.8 | 91.1 | 83.7 | 61.1 | 32.3 | 72.7 |
| Annual volume, mean | 265 | 274 | 244 | 179 | 98 | 212 |
| Delivery hospital | ||||||
| Level 3 (with tertiary NICU) | 9.4 | 26.3 | 35.5 | 37.8 | 23.7 | 26.5 |
| Annual volume, mean | 2 633 | 3 729 | 2 836 | 3 492 | 2 043 | 2 944 |
| Maternal | ||||||
| No. of records | 153 108 | 159 812 | 162 388 | 155 939 | 161 806 | 793 053 |
| Age, yr, mean | 29.3 | 30.5 | 29.0 | 29.3 | 28.3 | 29.3 |
| Income, $, mean† | 27 478 | 28 881 | 28 073 | 26 677 | 26 651 | 27 560 |
| Education, some high school† | 83.0 | 86.4 | 83.6 | 83.6 | 80.2 | 83.4 |
| Ethnicity, Aboriginal† | 3.5 | 3.5 | 4.8 | 5.9 | 10.8 | 5.7 |
| Urban (CMA or CA)† | 86.6 | 82.6 | 85.5 | 78.5 | 60.0 | 80.8 |
| Cesarean section | 29.6 | 29.0 | 28.7 | 29.0 | 28.9 | 29.0 |
| Prior cesarean section | 13.2 | 12.9 | 12.6 | 12.9 | 13.0 | 12.9 |
| Diabetes mellitus type 1 | 0.28 | 0.26 | 0.29 | 0.25 | 0.24 | 0.26 |
| Diabetes mellitus type 2 | 0.27 | 0.30 | 0.38 | 0.27 | 0.31 | 0.31 |
| Gestational diabetes mellitus | 4.5 | 4.8 | 4.4 | 5.9 | 4.0 | 4.7 |
| Eclampsia | 0.09 | 0.06 | 0.07 | 0.04 | 0.06 | 0.06 |
| PIH | 5.7 | 5.5 | 6.5 | 6.3 | 6.5 | 6.1 |
| HIV | 0.05 | 0.05 | 0.07 | 0.08 | 0.04 | 0.06 |
| Predicted maternal morbidity and mortality, per 1000‡ | 16.5 | 18.1 | 17.4 | 17.1 | 21.5 | 18.2 |
| Neonatal | ||||||
| No. of records | 154 485 | 161 694 | 165 297 | 155 606 | 162 741 | 799 823 |
| Sex, male | 51.2 | 51.2 | 51.3 | 51.4 | 51.2 | 51.3 |
| GA, wk, mean | 38.7 | 38.8 | 38.7 | 38.8 | 38.9 | 38.8 |
| Weight, g, mean | 3 357 | 3 340 | 3 376 | 3 363 | 3 416 | 3 371 |
| Twin | 2.6 | 3.1 | 2.9 | 3.0 | 2.6 | 2.9 |
| Triplet or greater | 0.10 | 0.13 | 0.09 | 0.06 | 0.06 | 0.09 |
| Congenital anomaly | 3.0 | 2.9 | 3.3 | 3.3 | 2.8 | 3.1 |
| Abruptio placenta | 0.12 | 0.10 | 0.31 | 0.17 | 0.14 | 0.17 |
| PROM | 0.30 | 0.26 | 1.39 | 0.64 | 0.32 | 0.59 |
| Predicted perinatal mortality, per 1000‡ | 4.8 | 4.5 | 4.5 | 4.4 | 4.3 | 4.5 |
Note: CA = census agglomeration, CMA = census metropolitan area, FP = family physician, GA = gestational age, NICU = neonatal intensive care unit, PIH = pregnancy-induced hypertension, PROM = premature rupture of membranes.
↵* Unless indicated otherwise.
↵† Data obtained at the census dissemination level.
↵‡ Mean predicted outcome rates calculated from a logistic regression model including all covariates except delivery provider.