Is Zyrtec safe during pregnancy?

What does the evidence say about Zyrtec during pregnancy?

1. Studies covering more than 1,300 pregnancies exposed to cetirizine have not found an increased chance of birth defects above the general population rate. 1
2. Loratadine (Claritin) has a similarly reassuring record: most studies haven't linked it to a higher chance of birth defects, and an early signal for a birth defect called hypospadias seen in one study wasn't confirmed by later research. 2
3. In a head-to-head trial at standard once-daily doses, cetirizine caused noticeably more daytime sleepiness and lower work motivation than loratadine, with the gap growing from mid-morning through mid-afternoon. 3
4. Small, occasional doses of cetirizine are considered acceptable while breastfeeding, though larger or longer-term doses may cause drowsiness in the nursing infant or reduce milk supply. 4
5. A larger study combining pregnancy outcomes with a review of similar research found no clinically important increase in the risk of poor fetal outcomes tied to cetirizine. 5

Is Zyrtec safe in each trimester?

• First trimester. Most of the reassuring safety data on cetirizine, including over 1,300 exposed pregnancies and a separate cohort study, covers first-trimester use, the window when major organs form, without any sign of increased birth-defect risk. If seasonal allergies or hives flare up early in pregnancy, a standard once-daily dose is a reasonable starting point to bring up with your prenatal team.
• Second trimester. Nasal congestion and allergy symptoms often get worse in the second trimester as blood volume and swelling increase, and cetirizine's safety profile doesn't change at this stage. Since it causes more daytime drowsiness than loratadine in head-to-head comparisons, this is a good time to check whether it still fits your work and driving schedule.
• Third trimester. No specific third-trimester risk to the baby has shown up in the data. Cetirizine does pass into breast milk in small amounts, so some clinicians suggest timing doses to avoid peak sleepiness around delivery and the first days of breastfeeding. Mention ongoing antihistamine use at your late-pregnancy visits so it can be part of your delivery and feeding plan.