Table 1.
Selected baseline characteristics of participants. Values are numbers (percentages) unless stated otherwise
| Characteristic | Vaccinated H1N1 (n=7293) | Non-vaccinated H1N1 (n=23 195) |
P value |
|---|---|---|---|
| Mean (SD) maternal age (years) | 25.8 (6.2) | 26.1 (6.4) | <0.01 |
| Age group: | |||
| <19 years | 519 (7.1) | 1349 (5.8) | <0.01 |
| 19-35 years | 5935 (81.4) | 18 808 (81.1) | |
| >35 years | 839 (11.5) | 3038 (13.1) | |
| Education: | |||
| <8 years | 2216 (30.4) | 8341 (36.0) | <0.01 |
| 8-12 years | 4582 (62.8) | 13 535 (58.4) | |
| >12 years | 392 (5.4) | 904 (3.9) | |
| Foreign women | 1287 (17.6) | 5081 (21.9) | <0.01 |
| Parity: | |||
| Nulliparous | 2860 (39.2) | 7608 (32.8) | <0.01 |
| Multiparous (>3 previous deliveries ) | 1234 (16.9) | 5094 (22.0) | |
| Stable partner/married | 6528 (89.5) | 20 750 (89.5) | NS |
| Use of illicit drugs | 32 (0.4) | 134 (0.6) | NS |
| Alcohol intake | 78 (1.1) | 188 (0.8) | NS |
| Smoker | 941 (12.9) | 2863 (12.3) | NS |
| Income*: | |||
| Poverty line | 1676 (23.0) | 3652 (15.7) | <0.01 |
| Poverty line ×2 | 3548 (48.6) | 11 236 (48.4) | |
| Poverty line ×3 | 520 (7.1) | 1786 (7.7) | |
| Mean (SD) previous maternal weight: | 61.3 (19.9) | 60.9 (14.4) | NS |
| <55 kg | 2386 (32.7) | 7085 (30.5) | NS |
| 55-85 kg | 4156 (57.0) | 12 105 (52.2) | |
| >85 kg | 347 (4.8) | 1077 (4.6) | |
| Antenatal visits: | |||
| None | 49 (0.7) | 909 (3.9) | <0.01 |
| 1-4 | 1181 (16.2) | 5722 (24.7) | |
| ≥5 | 6063 (83.1) | 16 534 (71.3) | |
| Gestational age at first antenatal visit: | |||
| <14 weeks | 3422 (46.9) | 7661 (33.0) | <0.01 |
| 15-20 weeks | 1795 (24.6) | 4996 (21.5) | |
| 20-28 weeks | 971 (13.3) | 3702 (16.0) | |
| >28 weeks | 471 (6.5) | 2742 (11.8) | |
| Previous stillbirth | 203 (2.8) | 593 (2.6) | NS |
| History of hypertension | 299 (4.1) | 844 (3.6) | <0.01 |
| History of pre-eclampsia | 74 (1.0) | 166 (0.7) | <0.01 |
NS=non-significant.
*Data were missing for 1549 (21.2%) vaccinated women and 6521 (28.1%) non-vaccinated women; smaller amounts of data were missing for other characteristics.