New Study Finds Benzodiazepine Miscarriage Risk

A new University of Montreal study has raised further questions about the safety of benzodiazepines during pregnancy. Benzodiazepines are prescribed for anxiety and insomnia and include the drugs Alprazolam (Xanax), Diazepam (Valium) and Clonazepam (Klonopin).

The study examined more than 160,000 pregnancies involving pregnant women taking benzodiazepines and found that they were nearly twice as likely to experience a miscarriage. Women with epilepsy as well as those who had previously used benzodiazepines or been exposed to confirmed toxins were excluded from the study. Furthermore, the study did not include women whose miscarriage occurred before six weeks or after 19 weeks.

“Anxiety and mood disorders need to be treated during pregnancy,” Professor Anick Berard, the study’s lead author, told JAMA Psychiatry. “Given the high prevalence of anxiety and mood disorders during pregnancy, physicians need to evaluate the risk and benefits of using benzodiazepines given that alternative nonpharmacologic treatments exist.

“Benzodiazepines are anxiolytics and signaling molecules,” said Berard. “It is believed that they disrupt binding and implantation when used in early pregnancy.”

There has already been controversy regarding the use of benzodiazepines during pregnancy. Previous studies demonstrated that they are passed into the placenta and can be linked to the development of birth defects. Furthermore, other studies had also indicated that benzodiazepines were a risk factor for miscarriage but were unable to distinguish between different classes of the drug.

The University of Montreal study found that women who used benzodiazepines during early pregnancy were 1.85 times more likely to miscarry than those who did not. Of those who miscarried, 1.4 percent had taken benzodiazepines in early pregnancy compared to 0.6 percent of those who successfully gave birth.

Tellingly, the researches found that all classes of the drug increased the risk of miscarriage, with diazepam the most dangerous, increasing the miscarriage risk by the 3.43 times when compared to non-benzodiazepine users.

The study showed the risk analysis for each class of benzodiazepine to be as follows:

  • Alprazolam: 2.02
  • Bromazepam: 2.34
  • Clonazepam: 1.77
  • Diazepam: 3.43
  • Flurazepam hydrochloride: 1.13
  • Lorazepam: 1.75
  • Oxazepam: 1.48
  • Temazepam: 2.74
  • Triazolam: 1.14

The main takeaway from the study:

The study was exhaustive and detailed so should inform the approach taken by doctors and psychiatrists when considering the prescription of benzodiazepines to pregnant women as well as women who may become pregnant.

As a consequence, alternatives to benzodiazepines should be considered – for example, other medications and/or talking therapies.

“An increased risk of miscarriage was observed among early pregnancies with incident exposure to short and long-acting benzodiazepines and all specific benzodiazepine agents during early pregnancy,” concluded the study’s authors. “Insomnia, anxiety, and mood disorders are prevalent during pregnancy; clinicians should carefully evaluate the risk/benefit ratio of prescribing benzodiazepines in early pregnancy since alternative nonpharmacologic treatments exist.”