Characteristics of women with low-risk singleton pregnancies resulting in a live or intrapartum stillbirth delivery in Ontario, Canada, between 2012 and 2018, by planned mode of delivery
| Characteristics | No. (%) of pregnancies* n = 422 210 | No. (%) of planned CDMR* n = 1827 | No. (%) of planned vaginal delivery* n = 420 383 | SMD |
|---|---|---|---|---|
| Maternal age, yr, mean ± SD | 29.7 ± 5.2 | 32.5 ± 5.7 | 29.7 ± 5.2 | 0.5 |
| Neighbourhood family income quintile | ||||
| Quintile 1 (lowest) | 92 362 (21.9) | 365 (20.0) | 91 997 (21.9) | 0.2 |
| Quintile 2 | 76 406 (18.1) | 288 (15.8) | 76 118 (18.1) | |
| Quintile 3 | 80 216 (19.0) | 307 (16.8) | 79 909 (19.0) | |
| Quintile 4 | 91 771 (21.7) | 414 (22.7) | 91 357 (21.7) | |
| Quintile 5 (highest) | 57 372 (13.6) | 332 (18.2) | 57 040 (13.6) | |
| Missing | 24 083 (5.7) | 121 (6.6) | 23 962 (5.7) | |
| Neighbourhood education level quintile† | ||||
| Quintile 1 (lowest) | 82 632 (19.6) | 246 (13.5) | 82 386 (19.6) | 0.3 |
| Quintile 2 | 88 891 (21.1) | 306 (16.7) | 88 585 (21.1) | |
| Quintile 3 | 84 780 (20.1) | 294 (16.1) | 84 486 (20.1) | |
| Quintile 4 | 86 618 (20.5) | 423 (23.2) | 86 195 (20.5) | |
| Quintile 5 (highest) | 58 489 (13.9) | 449 (24.6) | 58 040 (13.8) | |
| Missing | 20 800 (4.9) | 109 (6.0) | 20 691 (4.9) | |
| Maternal race | ||||
| White | 166 531 (39.4) | 886 (48.5) | 165 645 (39.4) | 0.2 |
| Asian | 67 274 (15.9) | 263 (14.4) | 67 011 (15.9) | |
| Black | 16 639 (3.9) | 44 (2.4) | 16 595 (3.9) | |
| Other | 15 208 (3.6) | 76 (4.2) | 15 132 (3.6) | |
| Missing | 156 558 (37.1) | 558 (30.5) | 156 000 (37.1) | |
| Nulliparous | 203 406 (48.2) | 1140 (62.4) | 22 266 (48.1) | 0.3 |
| Prepregnancy BMI, kg/m2, median (IQR) | 23.4 (20.9–27.2) | 23.2 (20.7–27.0) | 23.4 (20.9–27.2) | 0.05 |
| Gestational weight gain‡ | ||||
| Less than recommended | 100 444 (23.8) | 336 (18.4) | 100 108 (23.8) | 0.2 |
| Within recommended range | 81 936 (19.4) | 333 (18.2) | 81 603 (19.4) | |
| More than recommended | 199 721 (47.3) | 929 (50.8) | 198 792 (47.3) | |
| Missing | 40 109 (9.5) | 229 (12.5) | 39 880 (9.5) | |
| Conception type | ||||
| In vitro fertilization | 5484 (1.3) | 122 (6.7) | 5362 (1.3) | 0.3 |
| Intrauterine insemination and other ART | 5678 (1.3) | 38 (2.1) | 5640 (1.3) | |
| Spontaneous | 404 200 (95.7) | 1645 (90) | 402 555 (95.8) | |
| Missing | 6848 (1.6) | 22 (1.2) | 6826 (1.6) | |
| Maternal drug use during pregnancy§ | 8601 (2.0) | 31 (1.7) | 8570 (2.0) | 0.05 |
| Maternal alcohol use during pregnancy§ | 9637 (2.3) | 56 (3.1) | 9581 (2.3) | 0.05 |
| Maternal smoking§¶ | 43 374 (10.3) | 154 (8.4) | 43 220 (10.3) | 0.06 |
| Maternal anxiety§** | 34 571 (8.2) | 257 (14.1) | 34 314 (8.2) | 0.2 |
| Maternal depression§** | 30 676 (7.3) | 151 (8.3) | 30 525 (7.3) | 0.04 |
| Labour type | ||||
| Spontaneous | 321 253 (76.1) | 154 (8.4) | 321 099 (76.4) | 4.6 |
| Induced | 97 603 (23.1) | 0 (0.0) | 97 603 (23.2) | |
| No labour | 3322 (0.8) | 1673 (91.6) | 1649 (0.4) | |
| Missing | 32 (0.0) | 0 (0.0) | 32 (0.0) | |
| Antenatal health care provider†† | ||||
| Family physician only | 54 849 (13.0) | 60 (3.3) | 54 789 (13.0) | 0.6 |
| Obstetrician only | 233 439 (55.3) | 1445 (79.1) | 231 994 (55.2) | |
| Family physician and obstetrician | 58 909 (14.0) | 234 (12.8) | 58 675 (14.0) | |
| Midwife | 64 429 (15.3) | 61 (3.3) | 64 368 (15.3) | |
| None | S | S | 1530 (0.4) | |
| Other | 6694 (1.6) | 19 (1.0) | 6675 (1.6) | |
| Missing | S | S | 2352 (0.6) | |
| Maternity hospital level of care‡‡ | ||||
| Maternal Level I | 56 385 (13.4) | 134 (7.3) | 56 251 (13.4) | 0.4 |
| Maternal Level IIa | 47 765 (11.3) | 134 (7.3) | 47 631 (11.3) | |
| Maternal Level IIb | 133 875 (31.7) | 431 (23.6) | 133 444 (31.7) | |
| Maternal Level IIc | 108 030 (25.6) | 629 (34.4) | 107 401 (25.5) | |
| Maternal Level III | 76 099 (18.0) | 499 (27.3) | 75 600 (18.0) | |
| Missing | 56 (0.0) | 0 (0.0) | 56 (0.0) | |
| Infant sex, male | 215 860 (51.1) | 943 (51.6) | 214 917 (51.1) | 0.04 |
| Infant birth weight, g, mean ± SD | 3462.3 ± 448.3 | 3430.2 ± 427.1 | 3462.5 ± 448.4 | 0.07 |
| Gestational age, wk, median (IQR) | 39.9 (39.1–40.7) | 39.0 (38.7–39.4) | 39.9 (39.1–40.7) | 0.8 |
Note: ART = assisted reproductive technologies, BMI = body mass index, CDMR = cesarean delivery on maternal request, IQR = interquartile range, SD = standard deviation, SMD = standardized mean difference.
↵* Unless otherwise indicated. Column statistics are provided. Numbers are suppressed (S) for small cell sizes (n < 6).
↵† Percentage of college and university degrees among adults aged 25–64 years.
↵‡ Based on 2009 Institute of Medicine recommendations.
↵§ Self-reported variables.
↵¶ Captures any smoking at the first prenatal visit or at the time of labour or admission for delivery.
↵** 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.