Table 1.
Participant characteristics at the time of enrollment and duration of IM IFNβ-1a exposure
| Characteristic | Evaluable patients (N = 302) |
|---|---|
| Duration of MSa, years | |
| Mean (SD) | 4.6 (4.25) |
| Median (range) | 3.6 (0–24) |
| Age at enrollment, years | |
| Mean (SD) | 31.7 (5.57) |
| Median (range) | 31.0 (16–48) |
| Age category at enrollment, years, n (%) | |
| < 25 | 39 (12.9) |
| 25 to ≤ 35 | 182 (60.3) |
| > 35 | 81 (26.8) |
| Race/ethnicity, n (%) | |
| White | 196 (64.9) |
| Black | 70 (23.2) |
| Hispanic | 24 (7.9) |
| Asian | 2 (0.7) |
| Other | 10 (3.3) |
| Gestational week at enrollment | |
| Mean (SD) | 12.6 (7.4) |
| Median (range) | 10.1 (4–39) |
| Duration of IM IFNβ-1a exposure during pregnancy,b weeks | |
| Mean (SD) | 5.1 (5.1) |
| Median (range) | 4.1 (0–40) |
| Earliest exposure of IM IFNβ-1a during pregnancy, n (%) | |
| ≤ 1 week prior to conception | 278 (92.1) |
| First trimester | 24 (7.9) |
| Latest exposure of IM IFNβ-1a during pregnancy, n (%) | |
| ≤ 1 week prior to conception | 6 (2.0) |
| First trimester | 287 (95) |
| Second trimester | 5 (1.7) |
| Third trimester | 4 (1.3) |
IFNβ-1a interferon beta-1a, IM intramuscular, MS multiple sclerosis, SD standard deviation
aOne patient was diagnosed with clinically isolated syndrome, for which she was being treated with IM IFNβ-1a (301/302 patients diagnosed with MS)
bPatients with duration of exposure = zero ended therapy ≤ 1 week prior to conception