Table 1.
Characteristics of the two study populations
| Characteristic | CPRD | Liverpool and Manchester Neurodevelopment Groupa | ||
|---|---|---|---|---|
| Women with epilepsy [n (%)] | Comparator (no epilepsy) [n (%)] | Women with epilepsy [n (%)] | Comparator (no epilepsy) [n (%)] | |
| Mother–child pairs (n) | 1018 | 6048 | 201 | 214 |
| Mean maternal age at pregnancy (years) | 28.9 | 28.9 | 28 | 29 |
| Sex of the child (% male) | 50.2 | 50.2 | 57.1 | 51.9 |
| Smoking status | ||||
| Non-smoker | 506 (49.7) | 3308 (54.7) | 144 (71.6) | 180 (84.1) |
| Smoker | 360 (35.4) | 1759 (29.1) | 55 (27.4) | 34 (15.9) |
| Ex-smoker | 151 (14.8) | 968 (16.0) | ||
| Unknown | 1 (0.1) | 13 (0.2) | 2 (1.0) | 0 (0.0) |
| Alcohol drinking status | ||||
| Teetotal | 190 (18.7) | 853 (14.1) | 165 (82.1) | 148 (69.2) |
| Drinks alcohol | 684 (67.2) | 4388 (72.6) | 36 (17.9) | 66 (30.8) |
| Heavy drinker | 8 (0.8) | 42 (0.7) | ||
| Ex-drinker | 50 (4.9) | 181 (3.0) | ||
| Unknown | 86 (8.4) | 584 (9.7) | 2 (1.0) | 0 (0.0) |
| SES quintile | ||||
| 1 (least deprived) | 155 (15.2) | 921 (15.2) | ||
| 2 | 169 (16.6) | 1005 (16.6) | ||
| 3 | 202 (19.8) | 1195 (19.8) | ||
| 4 | 226 (22.2) | 1345 (22.2) | ||
| 5 (most deprived) | 266 (26.1) | 1582 (26.2) | ||
| Professional | 62 (30.8) | 87 (40.7) | ||
| Folic acid | ||||
| 5 mg in 6 months pre-pregnancyb | 196 (35.9) | |||
| Preconception use | 97 (48.3) | 85 (39.7) | ||
| Seizures during pregnancy | ||||
| Any record | 46 (4.5) | |||
| Convulsive | 68 (33.8) | |||
| Non-conclusive | 28 (13.9) | |||
CPRD Clinical Practice Research Datalink, SES socioeconomic status
aFigures provided via personal communication
bFolic acid figures restricted to only those prescribed an antiepileptic drug and to 5 mg as this strength is only available on prescription