Antihistamine Use During Pregnancy

Safety and Efficacy

Antihistamines, particularly second-generation options like cetirizine, are generally considered safe during pregnancy, with no evidence of harm to the fetus, according to the American Academy of Allergy, Asthma, and Immunology and the FDA 1, 2
Cetirizine and loratadine are classified as FDA Pregnancy Category B drugs, indicating no evidence of harm to the fetus during pregnancy, although well-controlled human studies are limited 2
The American College of Allergy, Asthma, and Immunology recommends second-generation antihistamines like cetirizine or loratadine as preferred options when antihistamine therapy is necessary during pregnancy 1
However, it is generally best to avoid all antihistamines during pregnancy if possible, especially during the first trimester, according to the British Association of Dermatologists 2

Cetirizine and loratadine are recommended as the second-generation antihistamines of choice for allergic rhinitis during pregnancy, by the American Academy of Allergy, Asthma, and Immunology 1
Chlorphenamine is often chosen by clinicians due to its long safety record, but second-generation antihistamines may be preferable due to less sedation 2, 3

The lowest effective dose for the shortest duration necessary should be used, as recommended by the FDA 2
Monitoring for maternal side effects is necessary, although these are less common with second-generation antihistamines like cetirizine, as stated by the American College of Allergy, Asthma, and Immunology 1

Non-pharmacological approaches should be considered first when possible, as recommended by the American Academy of Allergy, Asthma, and Immunology 1
If antihistamine treatment is necessary, preferred options include second-generation antihistamines (cetirizine, loratadine) or chlorphenamine, and diphenhydramine should only be used if benefits clearly outweigh potential risks 3

The first trimester is the most critical time for concern about potential congenital malformations, and antihistamine use should be avoided if possible during this period 3
Diphenhydramine should be used with caution during pregnancy, particularly in the first trimester, due to concerns about a possible association with cleft palate, although recent studies have not consistently confirmed this risk 3
If diphenhydramine is used, it is recommended to use the lowest effective dose for the shortest duration, avoid use during the first trimester if possible, and monitor for maternal side effects (sedation, anticholinergic effects) 3