Women who routinely use medications to manage allergies should consult a medical care provider about devising a treatment plan during pregnancy. When deciding on the best course of action, the woman and her health care provider must weigh the potential risks to the unborn baby and the benefits of the use of allergy medications. Women who have asthma and allergies are likely to continue using medications as an asthma attack could have severe consequences.
Chlorpheniramine
American Family Physician reports that chlorpheniarmine, an antihistamine, is considered a class B risk by the Food and Drug Administration. This classification means that either animal reproduction studies have demonstrated no fetal risk or some fetal risk but no human studies have been done or have replicated the same findings. A class B rating means the drug is considered to be safe during pregnancy, and chrlopheniramine is listed as the antihistamine of choice.
Diphenhydramine
Diphenhydramine is a class B antihistamine and antiemetic, which means it can reduce nausea and vomiting. American Family Physician confirms that the drug does cross the placenta, which means the fetus will be effected by the drug. There is a risk of an increase in oxytocin levels in the woman's body if high doses of the drug are taken. Oxytocin is a naturally occurring hormone that can cause contractions, especially in the later stages of pregnancy.
Clemastine Fumarate
Clemastine fumarate is a class B antihistamine that is relatively new compared to diphenhydramine and chlorpheniramine. FamilyDoctor.org suggests that older antihistamine drugs have been better studied or observed in pregnancy. For example, American Family Physician reveals that it is not known whether clemastine fumarate crosses the placenta to the baby and reports of its use in pregnancy are incomplete.
