Safety of Antihistamines During Pregnancy

If you're pregnant, you may wonder if it's safe to use antihistamines. These are commonly used to treat allergic rhinitis as well as insomnia, nausea, vomiting, motion sickness, and dizziness. Nearly 15% of pregnant women report taking an antihistamine during their first trimester.

Studies have shown that most antihistamines do not appear to be linked to birth defects and that certain medications, such as Zyrtec (cetirizine) and Claritin (loratadine), may be safe to use during pregnancy.

Study of Antihistamines in Pregnancy

A group of researchers from Boston Massachusetts and Singapore sought to determine the safety of antihistamines taken during the first trimester of pregnancy.

The researchers examined data collected over a 12-year period of time, from 1998 to 2010, on over 13,000 babies born with birth defects, and compared them to nearly 7,000 babies without birth defects.

Approximately 14% of all babies had been exposed to various antihistamines the mother took during the first trimester of pregnancy. Some antihistamines, such as Benadryl and Claritin, have increased in pregnancy use over the years, while the use of other antihistamines, such as Chlor-Trimeton and Unisom has decreased.

However, in an attempt to assess the risk of developing other common birth defects, the researchers did find an association between the use of Chlor-Trimeton and any neural tube defect and with various congenital heart malformations.

There was also an association between the use of Benadryl and one type of congenital heart malformation (transposition of the great arteries). However, the authors are careful to point out that these are only hypotheses that require further study.

In a 2014 study conducted by the Centers for Disease Control and Prevention (CDC), researchers reviewed 54 published scientific articles that examined the link between antihistamine use during pregnancy and birth defects.

They found that the use of most types of antihistamines during pregnancy is not linked to birth defects. However, the researchers noted that certain antihistamine medications need to be further studied to determine their safety in pregnancy.

Although research suggests that many antihistamines are generally considered “safe” during pregnancy, it's recommended that you consult with your healthcare provider before taking any over-the-counter medications.

Possible Associations Between Antihistamines and Birth Defects

Associations between antihistamines taken during the first trimester of pregnancy and certain birth defects include:

• Diphenhydramine (Benadryl): Cleft lip and cleft palate, neural tube defects, spina bifida, limb reduction defects, gastroschisis.
• Loratadine (Claritin): Hypospadias.
• Chlorpheniramine (Chlor-Trimeton): Eye defects, ear defects, spina bifida, cleft lip, and cleft palate.
• Doxylamine (Unisom): Cleft lip and cleft palate, pyloric stenosis, hypoplastic left heart syndrome, spina bifida, and neural tube defects.

Any medication taken during pregnancy is best taken for the shortest amount of time, and at the lowest dose that is effective for treating symptoms. The benefit of taking any medication needs to be weighed against the risk of not taking the medication.