Sheehy O, et al. - In this nested case-control study of the 442,066 pregnancies involved in the Quebec Pregnancy Cohort, researchers assessed the risk of spontaneous abortion (SA) correlated with gestational benzodiazepine incident use by drug class, duration of action, and particular benzodiazepine agent. Findings revealed that an increased risk of SA was independently associated with all benzodiazepine agents, and that any use of a benzodiazepine during early pregnancy was related to SA. The risk-benefit ratio of use of a benzodiazepine for the treatment of mood and anxiety disorders or insomnia during early pregnancy should be carefully appraised by health care professionals.