Is Cetirizine safe during pregnancy?

Pregnancy category and evidence

Cetirizine is a second-generation antihistamine that causes less sedation than first-generation agents like diphenhydramine. Under the former FDA system it was Category B. Decades of observational data — including Scandinavian and Israeli cohort studies totaling several thousand first-trimester exposures — show no significant increase in major congenital malformations. ACOG and ACAAI allergy-in-pregnancy guidelines consider cetirizine one of the preferred antihistamines during pregnancy.

By trimester

• First trimester (weeks 1–12): considered safe; no consistent signal for malformations. Acceptable for symptomatic allergy treatment when indicated.
• Second trimester (13–27): continues safe; often the trimester when allergy symptoms peak due to increased blood volume and congestion.
• Third trimester (28–40): safe; occasionally used with obstetrician approval near term.

Safer alternatives

Cetirizine is already among the preferred antihistamines. Equally acceptable alternatives in pregnancy include:

• Loratadine (second-generation, similar pregnancy safety profile — also ACOG-preferred)
• Chlorpheniramine (first-generation, longer track record, more sedating)
• Diphenhydramine (first-generation, widely used but sedating, short half-life)

Avoid first-generation antihistamines at term in high doses — some associations with neonatal irritability have been reported.

When it's acceptable and when to be cautious

• Acceptable: seasonal allergies, chronic urticaria, allergic rhinitis interfering with sleep or daily function.
• Preferred over decongestants: pseudoephedrine in first trimester has been associated with gastroschisis in some studies — use antihistamines + nasal saline first.
• Caution: combining cetirizine with other CNS depressants (alcohol — which itself to be avoided; benzodiazepines) amplifies sedation.
• Breastfeeding: small amounts transfer to breastmilk. Cetirizine is considered compatible with breastfeeding in LactMed.

Clinical sources

• FDA Pregnancy Labeling Rule narrative for Zyrtec (cetirizine).
• ACOG and ACAAI joint position paper "The use of newer asthma and allergy medications during pregnancy" (Annals of Allergy).
• Weber-Schoendorfer C et al. "Cetirizine in pregnancy: prospective comparative cohort." PMID: 18381252.
• LactMed database entry for cetirizine.

Bottom line

Cetirizine is among the safest antihistamines during pregnancy, with a large reassuring safety dataset. It's preferred over first-generation antihistamines for its lower sedation and better-studied profile. No trimester-specific restrictions apply at standard doses.

Discuss any medication use during pregnancy with your obstetrician, especially if you're taking multiple medications for allergies or asthma.