Antihistamine Use in Pregnancy

Introduction to Antihistamine Safety

Limited pregnancy data exists for levocetirizine, making it a less desirable option compared to its parent compound cetirizine, as noted by the American College of Allergy, Asthma, and Immunology 1
The first trimester is the most critical period when organogenesis occurs and medication-related congenital malformations are most likely, according to the American College of Obstetricians and Gynecologists 1
Second-generation antihistamines in general do not show a significant increase in congenital malformations when used during the first trimester, as reported by the American Academy of Allergy, Asthma, and Immunology 1

Large birth registries, case-control studies, and cohort studies confirm the safety of second-generation antihistamines like cetirizine during the first trimester, as recommended by the American College of Allergy, Asthma, and Immunology 1
Do not use oral decongestants during the first trimester due to conflicting reports of associations with gastroschisis and small intestinal atresia, as warned by the American College of Obstetricians and Gynecologists 1
Avoid diphenhydramine if possible due to lingering concerns about cleft palate association, as noted by the American Academy of Pediatrics 1

If a patient has had a uniquely favorable response to levocetirizine before pregnancy and other options have failed, discuss the limited safety data with the patient, as suggested by the European Academy of Allergy and Clinical Immunology 1
Use shared decision-making to weigh benefits versus theoretical risks when considering levocetirizine, as recommended by the National Institute for Health and Care Excellence 2

The American College of Obstetricians and Gynecologists recommends cetirizine as a preferred second-generation antihistamine for use during pregnancy based on extensive safety data, with benefits of symptom control outweighing theoretical risks, particularly for moderate to severe allergic rhinitis 3
First-generation antihistamines should be avoided during pregnancy due to sedative and anticholinergic properties, and some have been associated with congenital malformations, according to the FDA 4, 3

The American Academy of Allergy, Asthma, and Immunology suggests using cetirizine when the benefits of symptom control outweigh theoretical risks, and considering starting with non-pharmacologic measures first, such as saline nasal rinses, before adding cetirizine 3
Combining cetirizine with intranasal corticosteroids, particularly budesonide, is recommended for more severe symptoms, as these have strong safety data, according to the Journal of Allergy and Clinical Immunology 4, 3

Cetirizine and loratadine are the most well-studied second-generation antihistamines in pregnancy, making them preferable to newer agents, which have limited pregnancy data, as stated by the Journal of Allergy and Clinical Immunology 4

The European Respiratory Journal recommends cetirizine as a preferred antihistamine choice during pregnancy, particularly when antihistamine therapy is necessary for allergic conditions 5
Multiple guidelines from major respiratory and allergy societies, including those cited in the European Respiratory Journal and the Journal of Allergy and Clinical Immunology, recommend cetirizine or loratadine as preferred options when antihistamine therapy is needed during pregnancy 5, 6

Cetirizine and loratadine are classified as FDA Pregnancy Category B drugs, meaning there is no evidence of harm to the fetus during pregnancy, though well-controlled studies in humans are not available to exclude all harmful effects, as reported in the British Journal of Dermatology 7, 8
Avoid first-generation antihistamines like diphenhydramine due to lingering concerns about cleft palate association, as noted in the British Journal of Dermatology 7, 8