Table 1. Maternal, perinatal and child characteristics by exposure status.
| Normotensive (N = 60988) |
Preeclampsia/eclampsia (N = 2026) |
|
|---|---|---|
| Continuous variables | M (SD) | M (SD) |
| Maternal age at birth (years) | 28.3 (5.6) | 27.4 (5.9) |
| Gestational age at birth (days) | 279.3 (11.6) | 268.2 (19.8) |
| Categorical variables | n (%) | n (%) |
| Maternal marital status a | ||
| Married/cohabiting | 55798 (91.5) | 1822 (89.9) |
| Not married | 4262 (7.0) | 182 (9.0) |
| Widowed/divorced | 917 (1.5) | 22 (1.1) |
| Maternal occupational status a | ||
| Employed | 43093 (71.7) | 1464 (73.2) |
| Student | 6938 (11.5) | 322 (16.1) |
| Unemployed/welfare, other aid | 754 (1.3) | 37 (1.8) |
| Homemaker | 9329 (15.5) | 178 (8.9) |
| Maternal citizenship a | ||
| Icelandic | 59832 (98.1) | 1985 (98.0) |
| Foreign | 1152 (1.9) | 41 (2.0) |
| Place of birth | ||
| Urban | 41280 (67.7) | 1680 (82.9) |
| Rural | 19698 (32.3) | 346 (17.1) |
| Parity | ||
| Primipara | 22136 (36.3) | 1209 (59.7) |
| Multipara | 38852 (63.7) | 817 (40.3) |
| Singleton birth | ||
| Yes | 59109 (96.9) | 1831 (90.4) |
| No | 1879 (3.1) | 195 (9.6) |
| Infant sex | ||
| Boy | 30847 (50.6) | 1028 (50.7) |
| Girl | 30141 (49.4) | 998 (49.3) |
| Small for gestational age | ||
| No | 60058 (98.5) | 1827 (90.2) |
| Yes | 930 (1.5) | 199 (9.8) |
| 5-minute Apgar score | ||
| ≥7 | 59783 (98.0) | 1932 (95.4) |
| <7 | 1205 (2.0) | 94 (4.6) |
| ADHD prescriptions | ||
| Not present | 54901 (90.0) | 1807 (89.2) |
| Present | 6087 (10.0) | 219 (10.8) |
| Place of test administration b | ||
| Urban | 36253 (59.6) | 1255 (62.0) |
| Rural | 24618 (40.4) | 769 (38.0) |
| Test participation relative to peers | ||
| Concurrent with peers | 59129 (97.0) | 1969 (97.2) |
| Ahead of peers | 1783 (2.9) | 52 (2.6) |
| Behind peers | 76 (0.1) | 5 (0.2) |
SD, standard deviation; ADHD, attention-deficit/hyperactive disorder
a Some values were missing from the Medical Birth Register on maternal marital status (exposed n = 11), maternal occupational status (exposed n = 874; unexposed n = 25) and maternal citizenship (exposed n = 4).
b Some values were missing from the Directorate of Education on place of test administration (exposed n = 117; unexposed n = 2).