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Key Findings: Antihistamines and Birth Defects

Pregnant woman talking to doctor

Pregnant woman talking to her doctor about medication use.

In a new CDC study, researchers reviewed more than 50 published scientific articles to see if there was a risk of birth defects from using antihistamines, like allergy medication, during pregnancy. Researchers found the evidence to be generally reassuring: most antihistamines do not appear to be linked to birth defects. However, researchers need to study certain antihistamine medications further to determine if they increase the risk for birth defects. You can read the article’s abstract here. Read more below for a summary of the findings from this article.

Main findings from this study

  • Scientific research suggests that using most types of antihistamines during pregnancy is not linked to birth defects.
  • Out of 54 studies examined, 9 studies showed potential links between certain antihistamines and certain birth defects. Researchers need to study these potential links further.
  • Researchers found many studies on antihistamine medications typically used to treat allergies, asthma, or nausea and vomiting (H1-receptor antagonists).
    • Examples of H1-receptor antagonists include diphenhydramine (Benadryl®), dimenhydrinate (Dramamine®), loratadine (Claritin®), and cetirizine (Zyrtec®).
  • In contrast, researchers found relatively few studies on antihistamines typically used to treat indigestion (H2-receptor antagonists).
    • Examples of H2-receptor antagonists include ranitidine (Zantac®), famotidine (Pepcid®), and cimetidine (Tagamet®).

Remember

  • Talk with your doctor if you are pregnant and you have taken any medicine or are thinking of taking any medicine. This includes prescription and over-the-counter medications, as well as dietary or herbal products.
  • Pregnant women should not stop or start taking any type of medication that they need without first talking with a doctor.
  • If you are planning a pregnancy and are using any medications, please talk to your doctor about which medications are necessary and should be continued.

About antihistamines and this study

About antihistamines

Antihistamines include both prescription and over-the-counter medications. They typically are used to treat

  • Asthma and/or allergies;
  • Nausea and vomiting; or
  • Indigestion (heartburn or stomach ache).

About 10-15% of women report taking antihistamines during pregnancy.

About this study

Researchers reviewed more than 50 published scientific articles that looked at the link between antihistamine use during pregnancy and birth defects. They evaluated the articles based on certain criteria: how researchers selected their study populations, how researchers determined antihistamine use in pregnancy, and how researchers identified babies with birth defects.

Treating for Two: Safer Medication Use in Pregnancy

In collaboration with federal and external partners, CDC’s Treating for Two initiative is a national strategy to improve the health of mothers and babies through better research, reliable guidance, and informed decisions related to medication treatment in pregnancy.

  • Research: CDC funds the Centers for Birth Defects Research and Prevention, which collaborate on large studies such as the National Birth Defects Prevention Study (births 1997-2011) and the Birth Defects Study To Evaluate Pregnancy exposures (started with births in 2014). Researchers engaging in these studies work to identify factors that increase the risk for birth defects and to answer questions about the effects of some medications taken during pregnancy.
  • Technical expertise: CDC works with staff from the U.S. Food and Drug Administration (FDA) and other professionals to help conduct studies on the effects of medication use during pregnancy and ways to prevent harmful effects.
  • Collaboration: As part of the Treating for Two: Safer Medication Use in Pregnancy Initiative, CDC is committed to working with its partners, other federal agencies, and the public to build a comprehensive approach to improve the quality of data on medication use during pregnancy, translate this information into safe and effective health care for pregnant women, and make this information easily accessible to women and their healthcare providers.

More Information

For more information on medications and pregnancy, visit www.cdc.gov/treatingfortwo

Key Findings Reference

Gilboa SM, Ailes EC, Rai R, Anderson J, Honein MA. Antihistamines and Birth Defects: A Systematic Review of the Literature. Expert Opinion on Drug Safety. 2014. [epub ahead of print]

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