Table 1 Baseline characteristics of the study population, according to whether a woman had the composite outcome of maternal end-organ injury or death between 20 weeks’ gestation and up to 42 days after birth. All data are shown as a number (%) unless otherwise stated
Characteristic | With maternal end-organ injury or deatha (N = 1969) | Without maternal end-organ injury or death (N = 632,321) | Standardized difference |
|---|---|---|---|
Demographic factors, at conception | |||
Age, y | |||
Mean ± SD | 31.0 ± 5.9 | 29.6 ± 5.5 | 0.24 |
18–34 | 1414 (71.8) | 512,340 (81.0) | 0.22 |
35–39 | 428 (21.7) | 100,490 (15.9) | 0.15 |
40–44 | 112 (5.7) | 18,529 (2.9) | 0.14 |
≥ 45 | 15 (0.8) | 962 (0.2) | 0.09 |
Neighbourhood income quintile (Q) | |||
Q1 (lowest) | 521 (26.5) | 145,947 (23.1) | 0.08 |
Q2 | 388 (19.7) | 128,604 (20.3) | 0.02 |
Q3 | 422 (21.4) | 129,051 (20.4) | 0.03 |
Q4 | 370 (18.8) | 128,928 (20.4) | 0.04 |
Q5 (highest) | 268 (13.6) | 99,791 (15.8) | 0.06 |
World region of origin | |||
Western Nations and Europe | 69 (3.5) | 27,845 (4.4) | 0.05 |
Hispanic America | 47 (2.4) | 14,183 (2.2) | 0.01 |
Caribbean | 60 (3.0) | 10,305 (1.6) | 0.09 |
Sub-Saharan Africa | 80 (4.1) | 12,073 (1.9) | 0.13 |
Middle East and North Africa | 43 (2.2) | 18,138 (2.9) | 0.04 |
East Asia and Pacific | 139 (7.1) | 42,556 (6.7) | 0.01 |
South Asia | 166 (8.4) | 55,899 (8.8) | 0.01 |
Canada/Long-term resident | 1365 (69.3) | 451,322 (71.4) | 0.04 |
Infertility history identified in the index pregnancyb | 254 (12.9) | 49,231 (7.8) | 0.17 |
Any infertility treatment | 110 (5.6) | 18,449 (2.9) | 0.13 |
IVFc | 80 (72.7) | 9830 (53.3) | 0.41 |
Non-IVFc | 30 (27.3) | 8619 (46.7) | 0.41 |
Obstetrical factors in the index pregnancy | |||
Parity | |||
0 | 1004 (51.0) | 299,851 (47.4) | 0.07 |
1–2 | 823 (41.8) | 297,303 (47.0) | 0.11 |
≥ 3 | 142 (7.2) | 35,167 (5.6) | 0.07 |
Multiple gestation | 179 (9.1) | 18,149 (2.9) | 0.26 |
Had a first-trimester prenatal visit | 1296 (65.8) | 457,620 (72.4) | 0.14 |
Placental disorderd | 160 (8.1) | 12,020 (1.9) | 0.29 |
Median (IQR) gestational age at birth, weeks | 38 (36–39) | 39 (38–40) | 0.51 |
Obstetrical factors identified in any prior pregnancye | |||
Unplanned Caesarean birth | 340 (35.2) | 65,205 (19.6) | 0.36 |
Severe organ injury | 21 (1.1) | 482 (0.1) | 0.13 |
Preeclampsia, eclampsia or HELLP syndrome | 29 (3.0) | 5038 (1.5) | 0.1 |
Preterm birth < 37 weeks’ gestation | 90 (9.3) | 19,958 (6.0) | 0.13 |
Gestational diabetes mellitus | 57 (5.9) | 12,512 (3.8) | 0.1 |
Previous spontaneous abortion | |||
0 | 1426 (72.4) | 487,379 (77.1) | 0.11 |
1–2 | 486 (24.7) | 131,660 (20.8) | 0.09 |
≥ 3 | 57 (2.9) | 13,167 (2.1) | 0.05 |
Missing | ≤5 (0.0) | 116 (0.0) | 0.02 |
Medical factors identified within 365 days before the estimated date of conception in the index birth | |||
Median (IQR) body mass index, kg/m2f | 24.2 (24.2–24.2) | 24.2 (24.2–24.2) | 0.10 |
Body mass index category | |||
< 18.5 kg/m2 | 34 (1.7) | 11,622 (1.8) | 0.01 |
18.5–24.9 kg/m2 | 356 (18.1) | 116,614 (18.4) | 0.01 |
25–29.9 kg/m2 | 212 (10.8) | 56,016 (8.9) | 0.06 |
> 30 kg/m2 | 202 (10.3) | 44,644 (7.1) | 0.11 |
Missing | 1165 (59.2) | 403,425 (63.8) | 0.1 |
Obese (body mass index > 30 kg/m2 at any visit)f | 239 (12.1) | 54,493 (8.6) | 0.12 |
Median (IQR) body mass index, kg/m2 (without replacement)g | 25.2 (22.0–30.1) | 24.2 (21.3–28.5) | 0.17 |
Chronic hypertension | 156 (7.9) | 16,796 (2.7) | 0.24 |
Renal disease | 27 (1.4) | 758 (0.1) | 0.15 |
Diabetes mellitus (non-gestational) | 94 (4.8) | 10,203 (1.6) | 0.18 |
Dyslipidemia | 51 (2.6) | 12,161 (1.9) | 0.04 |
Cardiovascular morbidityh | 122 (6.2) | 12,469 (2.0) | 0.21 |
Systemic lupus erythematosus | 14 (0.7) | 722 (0.1) | 0.09 |
Asthma | 213 (10.8) | 43,376 (6.9) | 0.14 |
Other medical conditionsi | 7 (0.4) | 709 (0.1) | 0.05 |
Alcohol overuse | 14 (0.7) | 2654 (0.4) | 0.04 |
Any substance use | 76 (3.9) | 12,295 (1.9) | 0.11 |
Any tobacco use | 231 (11.7) | 72,387 (11.4) | 0.01 |