Characteristics of live births and stillbirths in Ontario from 2006 to 2014, according to mode of conception
| Characteristic | No. (%) of patients* | |||
|---|---|---|---|---|
| Spontaneous conception n = 688 970 | Subfertility without infertility treatment n = 78 283 | Noninvasive infertility treatment n = 9178 | Invasive infertility treatment n = 9633 | |
| Maternal age, yr, mean ± SD | 30.0 ± 5.3 | 33.1 ± 4.7 | 32.8 ± 4.4 | 35.4 ± 4.9 |
| < 25 | 108511 (15.75) | 2589 (3.31) | 230 (2.51) | 56 (0.58) |
| 25–29 | 200202 (29.06) | 14768 (18.86) | 1847 (20.12) | 907 (9.42) |
| 30–34 | 242387 (35.18) | 30741 (39.27) | 3906 (42.56) | 3313 (34.39) |
| 35–39 | 116043 (16.84) | 23340 (29.81) | 2538 (27.65) | 3542 (36.77) |
| 40–44 | 20964 (3.04) | 6465 (8.26) | 636 (6.93) | 1389 (14.42) |
| ≥ 45 | 863 (0.13) | 380 (0.49) | 21 (0.23) | 426 (4.42) |
| Income quintile | ||||
| 1 (lowest) | 149002 (21.6) | 12774 (16.3) | 1218 (13.3) | 929 (9.6) |
| 2 | 139654 (20.3) | 14300 (18.3) | 1603 (17.5) | 1528 (15.9) |
| 3 | 141676 (20.6) | 16509 (21.1) | 1922 (20.9) | 2070 (21.5) |
| 4 | 144089 (20.9) | 18818 (24.0) | 2484 (27.1) | 2619 (27.2) |
| 5 (highest) | 110703 (16.1) | 15697 (20.1) | 1934 (21.1) | 2468 (25.6) |
| Missing† | 3846 (0.6) | 185 (0.2) | 17 (0.2) | 19 (0.2) |
| Rural residence | 44483 (6.5) | 3047 (3.9) | 515 (5.6) | 348 (3.6) |
| Missing‡ | 8938 (1.3) | 334 (0.4) | 38 (0.4) | 28 (0.3) |
| Immigrant | 168131 (24.4) | 23972 (30.6) | 1853 (20.2) | 2522 (26.2) |
| Eligible for Ontario Drug Benefit | 76433 (11.1) | 5379 (6.9) | 629 (6.9) | 683 (7.1) |
| Primiparity§ | 283389 (41.1) | 39638 (50.6) | 5901 (64.3) | 6711 (69.7) |
| Multifetal pregnancy¶ | 8381 (1.2) | 2723 (3.5) | 1084 (11.8) | 2502 (26.0) |
| Gestational age at birth, wk, median (IQR)** | 39 (38–40) | 39 (38–40) | 39 (38–40) | 38 (37–40) |
| < 34 | 11027 (1.6) | 2303 (2.9) | 445 (4.9) | 765 (7.9) |
| 34+0–36+6 | 33349 (4.8) | 5272 (6.7) | 839 (9.1) | 1442 (15.0) |
| ≥ 37 | 644594 (93.6) | 70708 (90.3) | 7894 (86.0) | 7426 (77.1) |
| Cesarean birth | 217000 (26.8) | 33480 (36.2) | 4133 (38.7) | 5682 (50.6) |
| Stillbirth | 986 (0.1) | 164 (0.2) | 29 (0.3) | 41 (0.4) |
| Severe maternal morbidity composite†† | 12724 (1.9) | 1927 (2.5) | 250 (2.7) | 509 (5.3) |
| Comorbidities‡‡ | ||||
| Obesity§§ | 59807 (8.7) | 7530 (9.6) | 1406 (15.3) | 867 (9.0) |
| Smoking¶¶ | 61804 (9.0) | 2449 (3.1) | 252 (2.8) | 142 (1.5) |
| Substance use*** | 6167 (0.9) | 137 (0.2) | 21 (0.2) | 23 (0.2) |
| Alcohol use††† | 816 (0.1) | 41 (0.1) | 9 (0.1) | 6 (0.1) |
| Chronic hypertension | 15734 (2.3) | 2800 (3.6) | 367 (4.0) | 379 (3.9) |
| Diabetes mellitus | 9770 (1.4) | 2133 (2.7) | 263 (2.9) | 227 (2.4) |
Note: BORN = Better Outcomes Registry & Network, IQR = interquartile range, OHIP = Ontario Health Insurance Plan, SD = standard deviation.
↵* Unless indicated otherwise.
↵† In analyses, individuals with missing data were grouped with the lowest income quintile category.
↵‡ In analyses, individuals with missing data were grouped in the rural residence category.
↵§ In the BORN database 1.2% of total were missing. Any missing data from the BORN database were imputed using the parity variable from the MOMBABY database.
↵¶ < 0.5% missing in all categories. In analyses, individuals with missing data were grouped with singletons.
↵** In the BORN database < 0.2% of total were missing. In analyses, missing data were imputed with an algorithm for estimating gestational age based on hospital records with preterm status codes. (25)
↵†† From 20 weeks’ gestation up to 42 days postpartum (Appendix 1, eTable 4 contains the respective diagnostic codes).
↵‡‡ Based on hospital admissions, emergency department visits or outpatient physician visits within 2 years before conception and up to 19 weeks’ gestation.
↵§§ Diagnosis of obesity if maternal body mass index > 30 at time of birth in BORN database (missing 68%) or individual’s records included an OHIP billing code for obesity (278) in 2-year lookback period before estimated date of conception.
↵¶¶ In the BORN database, 8.2% of total were missing and grouped in the “no smoking” category for analyses.
↵*** Includes any use of marijuana, cocaine, gas or glue, hallucinogens, methadone, narcotics, opioids and other substance use. In the BORN database, 7.0% of total were missing and grouped in the “no substance use” category for analyses.
↵††† In the BORN database, 7.3% of total were missing and grouped in the “no alcohol use” category for analyses.