How risky is benzodiazepine use in pregnancy?

Early pregnancy exposure to any benzodiazepine was associated with an increased risk of miscarriage in women, according to a new study published in JAMA Psychiatry.

While previous research has linked pregnancy loss to this class of drugs, study researchers wanted to find out more about the exact risk of benzodiazepine use and miscarriage, which was defined as a pregnancy loss between the beginning of the sixth week and the 19th week of gestation.

Researchers analyzed data from more than 442,000 pregnancies from 1998 to 2015 in the Quebec Pregnancy Cohort, which includes data on all pregnancies of women covered by the Quebec Public Prescription Drug Insurance Plan. They found that the risk of miscarriage was greater when women took an increasing daily dose of a benzodiazepine, and that it didn’t matter which benzodiazepine they were exposed to. Similarly, the duration of action—short-acting and long-acting benzodiazepines—carried the same risk.

In their conclusion, the study authors wrote, “The findings suggest that health care clinicians should carefully evaluate the risk–benefit ratio of benzodiazepines for the treatment of insomnia and mood or anxiety disorders in early pregnancy. Alternative nonpharmacologic treatments exist and are recommended, but if benzodiazepines are needed, they should be prescribed for short durations.”

Authors explained that they at least partially corrected for diagnoses of mood and anxiety disorders and insomnia, as well as exposure to antidepressants and antipsychotics. However, other limitations of the study include tobacco and alcohol use that may not be accounted for.