Benzodiazepines associated with higher risk of miscarriage: Study

Benzodiazepines are often prescribed during pregnancy to treat anxiety, insomnia and mood disorders.
 
But a new study has linked the class of drugs to a heightened risk of miscarriage, leading to calls for increased caution around prescribing during early pregnancy.
 
The JAMA Psychiatry nested case-control study examined the risk of miscarriage associated with benzodiazepines in around 442,000 Canadian pregnancies between 1998 and 2015.
 
Of these, 6.1% of pregnancies ended in miscarriage, with 1.4% of those among women who used benzodiazepines in early pregnancy, compared to 0.6% of control pregnancies.
 
Australian National University (ANU) Professor of Medicine Julie Quinlivan said the study was important.
 
‘Clinicians need to be careful prescribing benzodiazepines at any time, but especially in pregnancy where the drugs can cross the placenta and affect the developing baby … If a clinician identifies a pregnant woman is using benzodiazepines in early pregnancy, they should seek advice from a specialist in order to identify alternative treatment options,’ she said.
 
‘There are only a few indications for prescribing benzodiazepines on the Pharmaceutical Benefits Scheme (PBS). For many patients there are alternative medications that can be used that do not lead to drug dependency. Often non-drug treatment options exist.’
 
Study lead author, Canadian Professor Anick Berard, said doctors had to carefully weigh risks versus benefits in comments to Medicalxpress.
 
‘In medications in pregnancy, physicians have to decide, are the risks higher than the benefits, because there isn't any risk zero,’ she said.
 
‘These findings suggest physicians should carefully evaluate the risks and benefits of prescribing benzodiazepines in early pregnancy since alternative treatments exist,’ the study states.
 
‘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 non-pharmacologic treatments exist.’
 
The study found all benzodiazepines were ‘independently associated with an increased risk of [spontaneous abortion].’
 
‘Benzodiazepines cross the placental barrier and accumulate in the fetal circulation at levels that are 1–3 times higher than the maternal serum levels,’ the study states.
 
In animal studies, benzodiazepines can interfere with fetal development in areas like neurodevelopment and immune system development.
 
The study follows a 2012 population-based study in the UK which found women who used benzodiazepines in early pregnancy had a 60% higher risk of miscarriage compared to women with non-medicated depression or anxiety.
 
The JAMA Psychiatry study did not take alcohol use into account, however.

benzodiazepines miscarriage pregnancy