- Exposure to any type of benzodiazepine early in pregnancy significantly increased the risk for spontaneous abortion (SA).
- SA risk increased with increasing daily benzodiazepine dose.
Why this matters
- Prior studies demonstrated the increased risk for pregnancy complications from prenatal exposure to benzodiazepines, but this is the first to examine the association between specific benzodiazepine agents and dose duration and SA risk.
- Nested case-control study of 26,789 pregnancies with SA and 134,305 control pregnancies during 1998-2015.
- Funding: Canadian Institutes of Health Research; Canadian Network for Advanced Interdisciplinary Methods.
- Cases were matched to 134,305 control pregnancies; approximately 5 controls were found for each of 26,789 (98.7%) of the cases.
- 1163 pregnancies were exposed to benzodiazepines in early pregnancy.
- Benzodiazepines most frequently prescribed were lorazepam (44.8%) and clonazepam (23.4%).
- Use of benzodiazepines during early pregnancy was associated with increased risk for SA vs nonuse (1.4% vs 0.6%; aOR, 1.85; P<.001>
- The risk for SA was significant with short-acting (aOR, 1.81; 95% CI, 1.55-2.12) and long-acting (aOR, 1.73; 95% CI, 1.31-2.28) benzodiazepines.
- Risk for SA increased with an increasing diazepam-equivalent daily dose of benzodiazepines (≤5 mg: aOR, 1.73; 6-20 mg: aOR, 1.96; and >20 mg: aOR, 2.55; P<.01>
- Information on smoking and alcohol intake was missing.
Coauthored with Antara Ghosh, PhD