Tavist and Pregnancy
Human studies on pregnancy and Tavist show that antihistamines seem to be fairly safe for pregnant women. However, using this type of medication during the last two weeks of pregnancy can increase the risk of retinopathy of prematurity. If you are taking this medication and pregnancy occurs, your healthcare provider will weigh the benefits and potential risks before making a recommendation for your particular situation.
Tavist® Allergy (clemastine fumarate) is a non-prescription medication used to treat allergies or the common cold. It is an antihistamine. Sometimes, antihistamines like Tavist are 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.
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 during pregnancy in humans (but have caused problems in laboratory animals) are also given a Category B rating.
In studies, giving very large doses of Tavist 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), antihistamines seem to be fairly safe for use during pregnancy. It should be noted that 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).