Table 1.
Characteristics of Study Participants
| Characteristic | Valproate Exposure, No. (%)
|
|
|---|---|---|
| Exposed (n = 508) | Not Exposed (n = 655 107) | |
| Maternal age at conception, y | ||
| <21 | 30 (5.9) | 26 212 (4.0) |
|
| ||
| 21-25 | 117 (23.0) | 127 230 (19.4) |
|
| ||
| 26-30 | 190 (37.4) | 262 707 (40.1) |
|
| ||
| 31-35 | 129 (25.4) | 180 973 (27.6) |
|
| ||
| ≥36 | 42 (8.3) | 57985 (8.9) |
|
| ||
| Paternal age at conception, y | ||
| ≤25 | 67 (13.6) | 76 700 (12.0) |
|
| ||
| 26-30 | 171 (34.7) | 213 912 (33.4) |
|
| ||
| 31-35 | 149 (30.2) | 211 993 (33.1) |
|
| ||
| ≥36 | 106 (21.5) | 138 337 (21.6) |
|
| ||
| Parental psychiatric historya | ||
| Yes | 43 (8.5) | 22 854 (3.5) |
|
| ||
| No | 465 (91.5) | 632 253 (96.5) |
|
| ||
| Gestational age, wk | ||
| <28 | 2 (0.4) | 1230 (0.2) |
|
| ||
| 28-31 | 9 (1.8) | 4616 (0.7) |
|
| ||
| 32-36 | 37 (7.3) | 36 556 (5.6) |
|
| ||
| ≥37 | 460 (90.6) | 612 705 (93.5) |
|
| ||
| Birth weight, g | ||
| <2500 | 46 (9.1) | 32 225 (4.9) |
|
| ||
| 2500-2999 | 69 (13.7) | 72 735 (11.2) |
|
| ||
| 3000-3499 | 147 (29.2) | 199 583 (30.6) |
|
| ||
| ≥3500 | 242 (48.0) | 346 785 (53.2) |
|
| ||
| Sex | ||
| Boys | 267 (52.6) | 335 843 (51.3) |
|
| ||
| Girls | 241 (47.4) | 319 249 (48.7) |
|
| ||
| Congenital malformationsb | ||
| Yes | 51 (10.0) | 25 568 (3.9) |
|
| ||
| No | 457 (90.0) | 629 539 (96.1) |
|
| ||
| Parity | ||
| 0 | 239 (47.0) | 283 054 (43.2) |
|
| ||
| ≥1 | 269 (53.0) | 372 047 (56.8) |
|
| ||
| Epilepsy (mother) | ||
| Yes | 432 (85.0) | 6152 (0.9) |
|
| ||
| No | 76 (15.0) | 648 955 (99.1) |
a
One or both parents diagnosed with a psychiatric disorder before birth of the child (International Classification of Diseases, Eighth Revision: codes 290-315; International Classification of Diseases, Tenth Revision [ICD-10]: All F codes).
b
Child diagnosed with congenital malformations (ICD-10 codes Q0 to Q99, except for Q53 and Q65 [see Methods]).