A large study of 442 066 pregnancies included in the Quebec Pregnancy Cohort, found that in 27 149 cases (6.1%) the outcome was spontaneous abortion, and amongst these women 375 (1.4%) were exposed to benzodiazepines in early pregnancy compared with 788 (0.6%) of 134 305 matched control pregnancies, yielding a crude OR of 2.39 (95% CI, 2.10-2.73). After adjustment for potential confounders, benzodiazepine exposure in early pregnancy was still associated with an increased risk of spontaneous abortion (adjusted OR, 1.85; 95% CI, 1.61-2.12) but the risk was similar for those using short-acting drugs and long-acting agents. Given that a range of issues that benzodiazepine are prescribed for are common during pregnancy the authors advocate that clinicians should carefully evaluate the risk/benefit ratio involved and consider non-pharmacological approaches instead. Read more here