pregnancy and benzodiazepines

Last edited 01/2024

• benzodiazepines cross the placenta - there is a risk of adverse effects in the fetus
  • during late pregnancy, or during labour, high doses may result in neonatal hypotonia and/or hypothermia. A mild neonatal respiratory distress may occur.
  • physical dependence may occur in infants born to mothers who take benzodiazepines chronically
  • benzodiazepines are excreted in the breast milk and therefore should not be given to lactating mothers
• use of both benzodiazepine anxiolytics and anxiety in pregnancy is associated with preterm delivery and low birth weight (2)
  • short-term neonatal effects of hypotonia, depression, and withdrawal are described
  • benzodiazepines are associated with physical dependence and withdrawal symptoms which can be serious

A case-time-control study, benzodiazepine use during pregnancy was associated with an increased risk of miscarriage, even after accounting for unmeasured confounders, including those related to genetics and the family environment (3):

• use of benzodiazepines during pregnancy was associated with an increased risk of miscarriage (OR 1.69, 95% CI 1.52-1.87)
  • for individual agents, ORs ranged from 1.39 (alprazolam) to 2.52 (fludiazepam
• the study authors stated that:
  • observation of an increased risk of miscarriage associated with benzodiazepine use during pregnancy suggests that benzodiazepines should only be used after a thorough evaluation of the potential benefits and risks for both the mother and child

Reference

1. CSM (1997), 23, 10.
2. Shyken JM, Babbar S, Babbar S, Forinash A. Benzodiazepines in Pregnancy. Clin Obstet Gynecol. 2019 Mar;62(1):156-167
3. Meng L, Lin C, Chuang H, Chen L, Hsiao F. Benzodiazepine Use During Pregnancy and Risk of Miscarriage. JAMA Psychiatry. Published online December 27, 2023. doi:10.1001/jamapsychiatry.2023.4912