Zykast (Cetirizine) Pregnancy Category
Cetirizine (Zykast) is classified as FDA Pregnancy Category B, indicating that animal reproduction studies have not demonstrated fetal risk, but there are no adequate and well-controlled studies in pregnant women. 1
Understanding Category B Classification
The FDA Pregnancy Category B designation means: 1, 2
- Animal reproduction studies have failed to demonstrate a risk to the fetus
- No adequate and well-controlled studies exist in pregnant women, OR
- Animal studies showed adverse effects that were not confirmed in controlled studies in women
Clinical Evidence Supporting Safety
The available human data on cetirizine use during pregnancy is reassuring:
A large safety database analysis of 228 pregnancies with maternal cetirizine exposure found that 83.7% resulted in live births, with only 2 congenital malformations reported among 41 live births—rates not exceeding background population rates 3
A prospective controlled study of 39 women exposed to cetirizine during organogenesis demonstrated no significant differences in pregnancy outcomes compared to controls, including rates of live births, spontaneous abortions, major or minor anomalies, birth weight, or gestational age 4
Most cetirizine exposures in reported pregnancies occurred during the first trimester when organogenesis takes place, without evidence of increased teratogenic risk 3
Practical Prescribing Guidance
The FDA drug label for cetirizine states: "if pregnant: ask a health professional before use" 5, reflecting the Category B classification where benefits may justify use despite limited human data.
For managing allergic rhinitis during pregnancy: 1
- Second-generation antihistamines like cetirizine have accumulated safety data comparable to first-generation antihistamines
- The Journal of Allergy and Clinical Immunology guidelines note that while there are limited data on cetirizine specifically, the overall safety profile of second-generation antihistamines supports their use when clinically indicated