The researchers discovered that the risk of miscarriage during the first trimester of pregnancy increased by 85% (from 6% to 11%) in women taking benzodiazepines. This class of anti-anxiety drugs contains names that are also known as Valium, Xanax and Ativan.
The association between the use of benzodiazepines and the increased risk of miscarriage is not new and has been noted by several other research teams. However, the results had little clinical value, what could be prescribed and in what dose.
Dr. Anick Bérard, an expert at CHU Sainte-Justine, one of the world's leading authorities in the field of pregnancy medication, and her colleagues studied data from more than 440,000 Canadian women who were between 1998 and 2015 were pregnant.
"At the clinic we want to know if benzodiaperine is prescribed and if so what is the safest?" She explained to the Canadian press from Paris. Regardless of the benzodiazine used, regardless of the mechanism of action, there appears to be an increased risk of miscarriage when these drugs are used early in pregnancy. "
Their study focused only on clinically observable miscarriages – and not on those that occur before the woman realizes she is pregnant – and only for women who first received benzodiazepines during their first trimester. of pregnancy.
The size of their cohort enabled them to refine the knowledge already available, to stratify the results according to how benzodiazines work: some are short-acting (less than 24 hours of action), others longer action (an effect after 24 hours), and researchers were able to look at all specific types, regardless of their mode of operation.
"Experimental studies with animals have shown that benzodiazepines […] during the first trimester it can interfere with the development of the fetus, said Dr. Bérard. Benzodiazepines were found to interfere with all signals […] who arrive during the first eight weeks of pregnancy to train the baby to come. "
However, it is not possible to say that this is what happens to people. Despite all the studies that have been conducted on this subject, the causal link between benzodiazepines and miscarriages has not yet been proven.
The authors of the study adjusted their results to take into account all other factors that could have an impact on miscarriages, but they only had partial data on the effects of smoking and alcohol use.
There is no reason to panic, but women who are worried about the situation should discuss this with their doctor, because the anxiety and insomnia that is treated by benzodiazepines can have a negative impact on pregnancy.
"There are still alternative non-pharmacological methods to relieve anxiety and mood disorders," Dr. said. Bérard. This study does not suggest not treating anxiety during pregnancy. I always say that the greatest strength that a pregnant woman can have is to have all the information at her disposal. The doctor is best placed to describe all the risks, but also all the possible benefits of taking a medication. […] If at the end of the discussion the woman and the doctor decide to take a benzodiazine, they will do so knowingly. "
The medical journal JAMA Psychiatry put the results of this study online this week.