Table 3. Obstetric Risk Factors in Nulliparous Women and Girls With ADHD by Age at Birth.
| Variable | Women and Girls, No (%) | Odds Ratio (95% CI) | |
|---|---|---|---|
| Aged ≥20 y (n = 5430) | Aged <20 y (n = 980) | ||
| Smoking during the first trimester | 1284 (24.8) | 375 (40.1) | 2.02 (1.75-2.34) |
| Smoking during the third trimester | 1001 (20.3) | 293 (34.0) | 2.02 (1.73-2.37) |
| Body mass indexa | |||
| <18.50 | 147 (3.0) | 54 (6.1) | 1.97 (1.42-2.73) |
| 18.50-24.99 | 2749 (55.2) | 512 (58.2) | 1 [Reference] |
| 25.00-29.99 | 1290 (25.9) | 212) (24.1) | 0.88 (0.74-1.05) |
| 30.00-34.99 | 523 (10.5) | 71 (8.1) | 0.73 (0.56-0.95) |
| 35.00-39.99 | 200 (4.0) | 21 (2.4) | 0.56 (0.36-0.89) |
| >40.00 | 68 (1.4) | 10 (1.1) | 0.79 (0.40-1.54) |
| Alcohol or substance use disorder | 415 (14.1) | 110 (11.2) | 1.05 (0.88-1.25) |
| Alcohol or substance use disorder during 12 mo preceding the pregnancy | 157 (5.3) | 50 (5.1) | 0.72 (0.53-0.98) |
| ADHD treatment during 12 mo preceding the pregnancy | 685 (23.3) | 341 (34.8) | 1.80 (1.55-2.08) |
| ADHD treatment during pregnancy | 213 (7.2) | 112 (11.4) | 1.73 (1.38-2.16) |
Abbreviation: ADHD, attention-deficit/hyperactivity disorder.
a
Calculated as weight in kilograms divided by height in meters squared.