Antihistamine use in early pregnancy not found to be related to birth defects

Published Online: September 16, 2013

Antihistamines are a group of medications that are used to treat various conditions, including allergies and nausea and vomiting. Some antihistamines require a prescription, but most are available over-the-counter (OTC), and both prescription and OTC antihistamines are often used by women during pregnancy. Until recently, little information was available to women and their health care providers on the possible risks and relative safety of these medications in pregnancy, particularly when it came to specific birth defects.

A new study from Boston University’s Slone Epidemiology Center, published recently in The Journal of Allergy and Clinical Immunology: In Practice, based on interviews with more than 20,000 new mothers, now provides important information for many of these medicines. The researchers considered antihistamines that had been suggested in earlier studies to increase risks of certain defects, and they also considered other possible risks that might not have been identified in the past. Where there was sufficient information in the study data, the authors found no evidence to support suggestions of risk that had been found in earlier studies. In considering possible risks that had not been identified by others, the investigators found very few suggestions that any given medicine might be linked to an increase risk of a specific birth defect, and though these few deserve further research attention, these findings may have been due to chance. The authors conclude that available information doesn’t suggest that antihistamine use in pregnancy poses substantially increased risks of birth defects.

An editorial by Drs. Honein and Moore entitled “The Safety or Risk of Antihistamine Use in Pregnancy: Reassuring Data are Helpful but not Sufficient” that accompanied this report, wisely advises clinicians that the planned use of antihistamines and other medication during pregnancy should still occur only after a thorough assessment of the risk versus the benefit based on each woman’s medical history and specific need for the medication. Moreover, when data exist regarding the relative safety or risk of medication, the safest option and lowest effective medication dose must be chosen when medication use is judged necessary. While the report of Li, et al, provide some reassuring safety data on antihistamines, more extensive information on more diverse outcomes will help both clinicians and patients make even better benefit/risk choices regarding use of antihistamines in pregnancy.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the American Academy of Allergy, Asthma & Immunology (AAAAI), focusing on practical information for the practicing clinician.

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