Antihistamines purchased over the counter (OTC) as well as those that require prescriptions have become so commonplace in the average American’s family medicine cabinet that they are often taken for granted. These medications are frequently used to breathe easier and to sleep more soundly but many a pregnant mother-to-be uses them to quell symptoms of nausea and vomiting associated with pregnancy. Some studies have hinted at a link between antihistamine consumption and increased risk of birth defects but, until now, the link has not been confirmed.

Mothers, rest assured. Your antihistamines are safe to use, be they purchased with or without a prescription. A team of medical research scientists at the Slone Epidemiology Center at Boston University Medical Center announced on September 16, 2013, that there is little, if any, apparent link between antihistamines and birth defects. The study evaluated the safety of both prescription and OTC antihistamines.

The majority of antihistamines consumed in the United States are purchased over the counter, without the need for a prescription. While many consumers erroneously consider OTC medications to be harmless, all medicines come with risk. All such risks intensify when a developing baby is exposed to them.

The Boston University Medical Center research team, led by Dr. Allen Mitchell, evaluated the risk in many commonly used OTC antihistamines as well as those available by prescription only. To do so, the team interviewed more than 20,000 mothers about their antihistamine use during pregnancy and the health of their babies. The team was looking especially for antihistamine-related links to certain birth defects.

Some birth defects were present in the study group but the Mitchell team found any link between increased risk of specific birth defects and antihistamines to be insignificant, suggesting instead that the birth defects identified in the study were more likely the result of chance rather than antihistamine consumption. Even so, Dr. Mitchell urges all women pregnant or considering becoming pregnant to let their healthcare provider know what medications they are taking, OTC or prescription.

The published findings of the study, titled “Assessment of Antihistamine Use in Early Pregnancy and Birth Defects,” are available in the current edition of the Journal of Allergy and Clinical Immunology: In Practice.


  • Qian Li, et al. "Assessment of Antihistamine Use in Early Pregnancy and Birth Defects." The Journal of Allergy and Clinical Immunology: In Practice, 2013. Web. 1 Oct 2013.
  • Boston University Medical Center. "Risk of birth defects among women who take antihistamines in pregnancy." ScienceDaily, 16 Sep. 2013. Web. 1 Oct. 2013.