| Asthmatic women | Non-asthmatic women | |||
| Pregnancies(n = 13100) | Perinatal deaths(n = 136) | Pregnancies(n = 28042) | Perinatal deaths(n = 217) | |
| n (%) | n (%) | n (%) | n (%) | |
| Maternal characteristics | ||||
| Age (years) | ||||
| <18 | 881 (6.7) | 9 (1.0) | 994 (3.6) | 9 (0.9) |
| 18–34 | 11411 (87.1) | 117 (1.0) | 24353 (86.8) | 173 (0.7) |
| ⩾35 | 808 (6.2) | 10 (1.2) | 2695 (9.6) | 35 (1.3) |
| Social assistance | ||||
| Yes | 10420 (79.5) | 113 (1.1) | 16091 (57.4) | 136 (0.9) |
| No | 2680 (20.5) | 23 (0.9) | 11951 (42.6) | 81 (0.7) |
| Level of education | ||||
| ⩽11 | 7795 (59.5) | 66 (0.9) | 11816 (42.2) | 85 (0.7) |
| ⩾12 | 4336 (33.1) | 23 (0.6) | 13925 (49.6) | 59 (0.6) |
| Missing | 969 (7.4) | 47 (4.9) | 2301 (8.2) | 73 (3.2) |
| Pregnancy-related variables | ||||
| Parity | ||||
| 1 | 4190 (32.0) | 34 (0.8) | 9620 (34.3) | 65 (0.7) |
| ⩾2 | 8843 (67.5) | 86 (1.0) | 18168 (64.8) | 132 (0.7) |
| PIH | ||||
| Yes | 845 (6.4) | 13 (1.5) | 1440 (5.1) | 11 (0.8) |
| No | 12255 (93.6) | 123 (1.0) | 26602 (94.9) | 206 (0.8) |
| Diabetes mellitus | ||||
| Yes | 309 (2.4) | 5 (1.6) | 368 (1.3) | 6 (1.6) |
| No | 12790 (97.6) | 130 (1.0) | 27670 (98.7) | 207 (0.8) |
| Gestational diabetes | ||||
| Yes | 1008 (7.7) | 11 (1.1) | 1899 (6.8) | 9 (0.5) |
| No | 12091 (92.3) | 124 (1.0) | 26139 (93.2) | 204 (0.8) |
| Placental abruption | ||||
| Yes | 486 (3.7) | 28 (5.8) | 844 (3.0) | 39 (4.6) |
| No | 12614 (96.3) | 108 (0.9) | 27198 (97.0) | 178 (0.7) |
| Infection of amniotic cavity | ||||
| Yes | 608 (4.6) | 18 (3.0) | 1407 (5.0) | 38 (2.7) |
| No | 12492 (95.4) | 118 (0.9) | 26635 (95.0) | 179 (0.7) |
| Fetal characteristics | ||||
| Cord around neck | ||||
| Yes | 2202 (16.8) | 14 (0.6) | 4990 (17.8) | 34 (0.7) |
| No | 10898 (83.2) | 122 (1.1) | 23052 (82.2) | 183 (0.8) |
| Birth weight | ||||
| ⩽2500 g | 1211 (9.2) | 97 (8.0) | 1599 (5.7) | 150 (9.4) |
| >2500 g | 11889 (90.8) | 39 (0.3) | 26443 (94.3) | 67 (0.3) |
| Gestational age at birth | ||||
| <37 weeks | 1359 (10.4) | 104 (7.7) | 1887 (6.7) | 146 (7.7) |
| ⩾37 weeks | 11741 (89.6) | 32 (0.3) | 26155 (93.3) | 71 (0.3) |
| SGA | ||||
| Yes | 1888 (14.4) | 27 (1.4) | 2954 (10.5) | 52 (1.8) |
| No | 11140 (85.0) | 102 (0.9) | 24876 (88.7) | 155 (0.6) |
PIH, pregnancy-induced hypertension; SGA, small for gestational age.