Hydroxyzine is not recommended during pregnancy. The product label advises pregnant women against using it, primarily because there isn’t enough human research to confirm its safety. That said, the existing studies (involving a few hundred women) haven’t found a clear increase in birth defects, which puts hydroxyzine in a gray area rather than a firm “no.” The real answer depends on your trimester, your dose, and whether safer alternatives would work for you.
What the Research Actually Shows
Hydroxyzine is classified as a pregnancy category C medication, meaning animal studies have shown harm to developing offspring at high doses, but well-controlled human studies are lacking. In animal research, hydroxyzine was teratogenic, meaning it caused birth defects, though at doses higher than what humans typically take.
The human data is limited but somewhat reassuring on the question of birth defects specifically. In studies involving over 200 women who used hydroxyzine throughout pregnancy, no increase in birth defects was reported. One small study of 100 women also found no increased chance of miscarriage. However, a separate study of 43 women with first-trimester exposure found a birth defect rate of about 4.6%, compared to 0% in unexposed women. These numbers come from very small sample sizes, so they’re hard to draw firm conclusions from.
The bottom line: the evidence doesn’t point to a major risk of birth defects, but researchers simply haven’t studied enough pregnancies to rule out smaller risks with confidence.
First Trimester vs. Later Pregnancy
Timing matters. First-trimester use carries the most concern because that’s when your baby’s organs are forming. Some research suggests hydroxyzine in the first trimester may increase the risk of fetal defects, though the data behind that claim is thin. It may also contribute to low blood pressure, involuntary muscle movements, and suppressed nervous system activity in the developing baby.
It’s not known whether hydroxyzine alone increases the chance of preterm delivery (before 37 weeks) or low birth weight (under 5 pounds, 8 ounces). These outcomes simply haven’t been studied well enough to say one way or the other.
Risks Near Delivery
Using hydroxyzine in the final weeks of pregnancy carries a specific and well-documented risk: neonatal withdrawal. Two cases have been reported in babies whose mothers took hydroxyzine in the four weeks before delivery. One infant had a seizure. The other experienced jitteriness, jerking movements, and feeding problems. While two cases may sound rare, the total number of women studied is also small, so the actual rate of withdrawal is unclear.
These withdrawal symptoms happen because the baby becomes accustomed to the medication in the womb and then suddenly loses exposure at birth. If you’re currently taking hydroxyzine and are approaching your due date, tapering off under medical guidance is the typical approach rather than stopping abruptly.
Hydroxyzine and Breastfeeding
There’s very little data on how much hydroxyzine passes into breast milk. No studies have measured actual drug levels in milk or in nursing infants. What does exist is a collection of adverse reaction reports: out of 174 reports on antihistamines and breastfeeding, hydroxyzine was linked to adverse reactions in 8 infants, mostly sedation. It was flagged as one of the antihistamines most often suspected of causing serious reactions in nursing babies.
In a broader survey of mothers taking various antihistamines while breastfeeding, about 10% reported irritability or colic-like symptoms in their infants, and 1.6% reported drowsiness. None of those reactions required medical attention.
Safer Alternatives Worth Discussing
If you need an antihistamine during pregnancy for allergies, itching, or nausea, several options have stronger safety profiles than hydroxyzine. The American College of Obstetricians and Gynecologists and the American College of Allergy, Asthma and Immunology recommend chlorpheniramine and tripelennamine as first-choice antihistamines for pregnant women. Both are older, first-generation drugs with decades of use and reassuring safety data in both animal and human studies.
If those don’t work well enough or you can’t tolerate their side effects (mainly drowsiness), cetirizine (Zyrtec) and loratadine (Claritin) are considered reasonable second-line options after the first trimester. Both are category B medications, meaning animal studies haven’t shown risk and there’s moderate human data supporting their safety. Loratadine was once suspected of increasing the risk of a genital birth defect called hypospadias, but more recent studies have ruled that out.
If you’re taking hydroxyzine specifically for anxiety rather than allergies, the conversation with your provider looks different. Antihistamines aren’t the only option, and the risk-benefit calculation changes depending on how severe your anxiety is and how far along you are. What matters most is not stopping any medication abruptly without a plan, since untreated anxiety during pregnancy carries its own risks for both you and your baby.