Table 2. Associations Between Pregnancy Benzodiazepine Use and Risk of Miscarriage: Case-Time-Control (CTC) Design.
| Main analysis | Exposed during the risk period only, No.a | Exposed during the reference period only, No.b | OR (95% CI) |
|---|---|---|---|
| Overall benzodiazepine | |||
| CCO individuals with miscarriage | 1502 | 2806 | 0.54 (0.50-0.57) |
| CCO control individuals | 753 | 2386 | 0.32 (0.29-0.34) |
| CTC ratio | NA | NA | 1.69 (1.52-1.87) |
| Long-acting benzodiazepine | |||
| CCO individuals with miscarriage | 677 | 1358 | 0.50 (0.46-0.55) |
| CCO control individuals | 354 | 1202 | 0.30 (0.26-0.33) |
| CTC ratio | NA | NA | 1.67 (1.44-1.93) |
| Short-acting benzodiazepine | |||
| CCO individuals with miscarriage | 1083 | 1883 | 0.58 (0.54-0.62) |
| CCO control individuals | 555 | 1579 | 0.35 (0.32-0.39) |
| CTC ratio | NA | NA | 1.66 (1.47-1.87) |
Abbreviations: CCO, case-crossover; NA, not applicable; OR, odds ratio.
a
Risk period was defined as 1 to 28 days before miscarriage.
b
Reference period was defined as 181 to 208 days before the last menstrual period.