Table I.
Comparison of baseline characteristics among women with and without benzodiazepine prescriptions before conception (n = 1 691 366).
| Characteristic | Had a benzodiazepine prescription a (n = 17 990) | Did not have any benzodiazepine prescriptions (n = 1 673 376) |
|---|---|---|
| No. (%) | No. (%) | |
| Age | ||
| 15–19 | 427 (2.37) | 84 219 (5.03) |
| 20–24 | 2330 (12.95) | 199 522 (11.92) |
| 25–29 | 4183 (23.25) | 449 669 (26.87) |
| 30–34 | 5901 (32.80) | 561 771 (33.57) |
| 35–39 | 3856 (21.43) | 298 499 (17.84) |
| 40–44 | 1293 (7.19) | 79 696 (4.76) |
| Year | ||
| 2008–2011 | 7578 (42.12) | 760 223 (45.43) |
| 2012–2015 | 10 412 (57.88) | 913 153 (54.57) |
| Medical conditions in the 9 months before the exposure period b | ||
| Sexually transmitted infection | 280 (1.56) | 17 166 (1.03) |
| Assisted reproductive technology | 119 (0.66) | 7135 (0.43) |
| Pelvic infection | 163 (0.91) | 5973 (0.36) |
| Intrauterine device | 585 (3.25) | 42 018 (2.51) |
| Smoking | 1451 (8.07) | 26 828 (1.60) |
a
aHad at least two benzodiazepine prescriptions totaling at least 10 days’ supply in the 90 days before conception
b
bExposure period is the 90 days before conception