Factors associated with planned CDMR in Ontario, Canada, between 2012 and 2018*
| Factor | No. of pregnancies* n = 422 210 | No. (%) of planned CDMR n = 1827 | Adjusted OR (95% CI)† |
|---|---|---|---|
| Maternal age, yr | |||
| < 19 | 12 462 | 29 (0.23) | 0.53 (0.37 to 0.77) |
| 20–34 | 334 278 | 1140 (0.34) | Reference |
| 35–39 | 63 896 | 459 (0.72) | 2.11 (1.88 to 2.37) |
| ≥ 40 | 11 393 | 195 (1.71) | 4.33 (3.67 to 5.11) |
| Neighbourhood family income quintile | |||
| Quintile 1 (lowest) | 92 362 | 365 (0.40) | Reference |
| Quintile 2 | 76 406 | 288 (0.38) | 0.94 (0.79 to 1.10) |
| Quintile 3 | 80 216 | 307 (0.38) | 0.91 (0.78 to 1.06) |
| Quintile 4 | 91 771 | 414 (0.45) | 0.96 (0.83 to 1.11) |
| Quintile 5 (highest) | 57 372 | 332 (0.58) | 0.93 (0.79 to 1.11) |
| Neighbourhood education level quintile‡ | |||
| Quintile 1 (lowest) | 82 632 | 246 (0.30) | Reference |
| Quintile 2 | 88 891 | 306 (0.34) | 1.06 (0.89 to 1.27) |
| Quintile 3 | 84 780 | 294 (0.35) | 1.02 (0.85 to 1.22) |
| Quintile 4 | 86 618 | 423 (0.49) | 1.30 (1.10 to 1.54) |
| Quintile 5 (highest) | 58 489 | 449 (0.77) | 1.78 (1.48 to 2.15) |
| Maternal race | |||
| White | 166 531 | 886 (0.53) | Reference |
| Non-White | 99 121 | 383 (0.39) | 0.60 (0.53 to 0.68) |
| Missing | 156 558 | 558 (0.36) | 0.87 (0.78 to 0.97) |
| Parity | |||
| 0 | 203 406 | 1140 (0.56) | 2.25 (2.02 to 2.50) |
| ≥ 1 | 218 804 | 687 (0.31) | Reference |
| Prepregnancy BMI, kg/m2 | |||
| Underweight (< 18.5) | 24 499 | 123 (0.50) | 1.24 (0.99 to 1.57) |
| Normal weight (18.5 to 24.9) | 211 790 | 896 (0.42) | Reference |
| Overweight (25.0 to 29.9) | 89 491 | 348 (0.39) | 0.93 (0.81 to 1.07) |
| Obese (≥ 30) | 56 322 | 231 (0.41) | 1.00 (0.87 to 1.16) |
| Gestational weight gain§ | |||
| Less than recommended | 100 444 | 336 (0.33) | 0.88 (0.75 to 1.04) |
| Within recommended range | 81 936 | 333 (0.41) | Reference |
| More than recommended | 199 721 | 929 (0.47) | 1.18 (1.04 to 1.34) |
| Conception type | |||
| In vitro fertilization | 5484 | 122 (2.22) | 2.64 (2.15 to 3.24) |
| Intrauterine insemination and other ART | 5678 | 38 (0.67) | 1.05 (0.75 to 1.45) |
| Spontaneous | 404 200 | 1645 (0.41) | Reference |
| Maternal anxiety¶** | |||
| No | 387 639 | 1570 (0.41) | Reference |
| Yes | 34 571 | 257 (0.74) | 2.07 (1.79 to 2.40) |
| Maternal depression¶** | |||
| No | 391 534 | 1676 (0.43) | Reference |
| Yes | 30 676 | 151 (0.49) | 0.97 (0.81 to 1.17) |
| Attended prenatal class | |||
| No | 288 368 | 1283 (0.44) | Reference |
| Yes | 101 394 | 392 (0.39) | 0.59 (0.52 to 0.67) |
| Antenatal health care provider†† | |||
| Family physician only | 54 849 | 60 (0.11) | 0.21 (0.16 to 0.27) |
| Obstetrician only | 233 439 | 1445 (0.62) | Reference |
| Family physician and obstetrician | 58 909 | 234 (0.40) | 0.72 (0.63 to 0.83) |
| Midwife | 64 429 | 61 (0.09) | 0.16 (0.13 to 0.21) |
| None | S | S | S |
| Other | 6694 | 19 (0.28) | 0.48 (0.30 to 0.76) |
| Maternal hospital level of care‡‡ | |||
| Level I | 56 385 | 134 (0.24) | Reference |
| Level IIa | 47 765 | 134 (0.28) | 0.86 (0.68 to 1.10) |
| Level IIb | 133 875 | 431 (0.32) | 0.91 (0.75 to 1.12) |
| Level IIc | 108 030 | 629 (0.58) | 1.57 (1.30 to 1.91) |
| Level III | 76 099 | 499 (0.66) | 1.51 (1.24 to 1.85) |
| Infant sex | |||
| Male | 215 860 | 943 (0.44) | Reference |
| Female | 206 101 | 884 (0.43) | 0.97 (0.89 to 1.07) |
| Birth weight, g | |||
| < 2500 | 4259 | 10 (0.23) | 0.50 (0.27 to 0.93) |
| 2500 to 3999 | 368 153 | 1643 (0.45) | Reference |
| ≥ 4000 | 49 782 | 174 (0.35) | 0.87 (0.74 to 1.02) |
Note: ART = assisted reproductive technologies, BMI = body mass index, CDMR = cesarean delivery on maternal request, CI = confidence interval, OR = odds ratio.
↵* Counts included in table are identical to Table 1 and are based on data before imputation. Row percentages are presented. Adjusted relative risk estimates were calculated using data imputed using fully conditional specification. Numbers are suppressed (S) for small cell sizes (n < 6).
↵† A multivariate logistic regression model was used to estimate the adjusted odds ratios. The multivariate logistic regression model included maternal age, neighbourhood income level, neighourhood education level, race, parity, BMI, gestational weight gain, method of conception, prenatal class attendance, anxiety, depression, antenatal health care provider, maternal hospital level of care, infant sex and infant birth weight. If one independent variable was treated as the main predictor, the other variables were automatically treated as covariates or confounders. C-statistic = 0.746.
↵‡ Percentage of college and university degrees among adults 25–64 years old.
↵§ Based on 2009 Institute of Medicine recommendations.
↵¶ Self-reported variables.
↵** Constitute concerns that were pre-existing, diagnosed during pregnancy or active during pregnancy.
↵†† If a woman had a midwife in addition to other health care providers, she was assigned to the midwife group. The assumption was that most of the antenatal care would have been provided by the midwife.
↵‡‡ Maternal hospital level of care classification based on newborn and maternal needs, risk and illness as defined by The Provincial Council for Maternal and Child Health in Ontario.