Benadryl and Pregnancy
Based on animal studies on pregnancy and Benadryl, the medication does not appear to present a risk to a developing fetus. In small human studies, the drug also appeared to be fairly safe for use during pregnancy. In fact, Benadryl is sometimes used "off-label" to treat severe morning sickness. If you are taking this medicine and pregnancy occurs, be sure to let your healthcare provider know.
Is Benadryl Safe During Pregnancy?
Benadryl® (diphenhydramine hydrochloride) is an antihistamine often used for allergies. The active ingredient in Benadryl is also frequently used as a sleep aid. Sometimes, Benadryl is used "off-label" for the treatment of severe morning sickness. Based on animal studies, this medication does not appear to present a risk to a developing fetus, although the full effects in humans are not currently known.
Pregnancy Category B
The U.S. Food and Drug Administration (FDA) uses a pregnancy category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category B is given to medicines that have not been adequately studied in pregnant humans but do not appear to cause harm to the fetus in animal studies. Medications that have been shown to be safe for use in pregnant humans (but have caused problems in laboratory animals) are also given a Category B rating.
In studies, giving very large doses of Benadryl to pregnant rabbits and rats did not increase the risks of any problems. In human studies (which have not been adequate enough to fully characterize the safety of the medication), Benadryl seems to be fairly safe for use during pregnancy. There is some preliminary evidence that it might increase the risk of cleft palate, but these early findings need to be confirmed by further research. Also, the use of antihistamines in general during the last two weeks of pregnancy seems to increase the risk of retinopathy of prematurity (an eye problem in premature infants that can lead to blindness).