Cetirizine

Pregnancy

MotherToBaby reports that studies involving over 1,300 cetirizine-exposed pregnancies did not show a higher chance of birth defects. Its sheet separately says several small studies did not find a higher chance of miscarriage, and a small number of pregnancies did not show a higher chance of preterm delivery or low birth weight; it gives no trimester-specific estimates. Einarson et al. (1997) followed 39 cetirizine exposures and found no significant differences in pregnancy outcomes. Weber-Schoendorfer et al. (2008) compared 196 first-trimester exposures with 1,686 controls and found no significant differences in major birth defects, miscarriage, preterm delivery, or term birth weight. Etwel et al. (2014) found no increased teratogenic risk for cetirizine alone, but a marginal association when cetirizine and hydroxyzine studies were combined. Källén (2002) studied 17,266 women and 17,776 deliveries, but analyzed antihistamine use broadly and did not report a cetirizine-only count. Golembesky et al. (2018) used UCB Pharma's safety database; outcomes were available for 228 of 522 exposure reports, and 49 were prospective. Lisiecka and Luczak (2026) reviewed 45 sources and reported no statistically significant associations between second-generation antihistamines and several pregnancy outcomes, but their abstract does not isolate cetirizine for each result. Kermani et al. (2026) described fetal SVT after cetirizine plus an antihistamine-decongestant; this co-exposure cannot identify which medicine caused the event.

Breastfeeding

LactMed (last revised 15 September 2025) says small occasional doses are acceptable and larger or longer use may cause infant drowsiness or other effects, or decrease milk supply, especially with pseudoephedrine or before lactation is well established. Wilkerson et al. (2021) reported a relative infant dose of 1.77% at 24 hours and no reported infant adverse effects; the abstract does not state a participant count. Nordeng et al. (2024) included 32 women, 31 using cetirizine, and estimated a 1.9% relative infant dose with no severe adverse events. LactMed reports that 10 of the 31 women perceived a decrease in milk supply over the prior 3 days, but the PubMed abstract does not report this number and the full article was not available for verification. Melander et al. (2025) modeled data from a lactation study of 35 women and 205 milk samples and estimated a mean relative infant dose of 1.99%; this modeling uses lactation-study data and is not a separate cohort. LactMed and NHS interpret the low milk levels as compatible with breastfeeding, while the Kenvue OTC label says breastfeeding use is not recommended.

What was tested

Pregnancy evidence includes Einarson et al. (1997) and Weber-Schoendorfer et al. (2008) prospective cohorts, Källén's (2002) registry analysis, Etwel et al.'s (2014) meta-analysis, and Golembesky et al.'s (2018) manufacturer database study. These studies assessed major birth defects, miscarriage, preterm delivery, birth weight, and other pregnancy outcomes; most do not provide trimester-specific cetirizine estimates. Wilkerson et al. (2021) and Nordeng et al. (2024) measured milk concentrations and estimated infant exposure, with limited infant outcome follow-up; Melander et al. (2025) modeled lactation-study data. Nordeng et al. included women at least 8 weeks postpartum and 31 cetirizine users; its PubMed abstract does not report the milk-supply perception count cited by LactMed. MotherToBaby's fact sheet says later child behavior and learning have not been studied.