Antihistamines in Pregnancy: What’s Safe and What to Avoid

When you’re pregnant and your nose is stuffed up, your eyes are itchy, and you can’t sleep because of hives, the last thing you want is to suffer in silence. But the moment you reach for that bottle of allergy pills, a question pops up: is this safe for my baby? You’re not alone. Thousands of pregnant people face this same dilemma every year. The good news? There are options. The tricky part? Knowing which ones actually work without putting your baby at risk.

First-Generation vs. Second-Generation Antihistamines: The Big Difference

Not all antihistamines are the same. They’re split into two main groups, and the difference matters a lot during pregnancy.

First-generation antihistamines - like chlorpheniramine (ChlorTrimeton) and diphenhydramine (Benadryl) - have been around for decades. They work well, but they make you sleepy. That’s because they cross the blood-brain barrier. For some pregnant people, that drowsiness is a relief - if you’re exhausted from insomnia caused by allergies, a little sleep might be worth it. But if you’re driving, working, or caring for other kids, that drowsiness can be dangerous.

Second-generation antihistamines - like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) - were designed to avoid that drowsiness. They barely enter the brain, so you stay alert. That’s a big plus. But because they’re newer, people worry more about long-term safety. The truth? The data we have now is reassuring. Large studies haven’t found a clear link between these drugs and birth defects.

Chlorpheniramine is often the go-to first-gen choice among doctors because it’s been used safely since the 1950s. Diphenhydramine works too, but it’s shorter-acting and can cause more drowsiness. If you’re choosing between them, chlorpheniramine usually wins for consistency.

What the Experts Say About Safety

Major medical groups agree on one thing: untreated severe allergies can be risky. If you can’t eat because your nose is blocked, or you’re too itchy to sleep, or your asthma flares up, that stress and lack of oxygen can affect your baby too.

The American College of Obstetricians and Gynecologists (ACOG) updated its guidance in March 2025 and says chlorpheniramine and dexchlorpheniramine are safe options. For newer drugs like loratadine and cetirizine, they say they “may also be safe” - meaning the evidence isn’t perfect, but it’s strong enough to support use when needed.

The Mayo Clinic recommends loratadine and cetirizine as first-line choices for mild allergy symptoms during pregnancy. Why? Because decades of data show no increase in birth defects. The American Academy of Family Physicians (AAFP) backs this up, giving both first- and second-generation antihistamines an evidence rating of B - meaning “benefits likely outweigh risks.”

The CDC analyzed over 14 antihistamines across thousands of pregnancies and found no consistent pattern of birth defects. One small study hinted at a possible link between hydroxyzine and heart defects, but that was based on only seven cases. That’s not enough to say it’s dangerous - just not enough to say it’s completely risk-free. So most doctors avoid hydroxyzine during pregnancy.

Which Antihistamines Are Recommended?

Here’s what most doctors in Australia, the U.S., and Europe actually recommend:

• Loratadine (Claritin, Alavert) - Non-sedating, taken once daily. Best for mild seasonal allergies. Over 10,000 pregnancies studied with no increased risk of major birth defects.
• Cetirizine (Zyrtec) - Also non-sedating for most people. A few report mild drowsiness, but it’s rare. One of the most studied antihistamines in pregnancy.
• Chlorpheniramine (ChlorTrimeton) - Sedating, but the most proven safety record. Often used if other options don’t work or if sleep is the goal.
• Fexofenadine (Allegra) - Less studied than loratadine or cetirizine, but no red flags so far. Often used as an alternative if one doesn’t work.

There’s no single “best” choice. It depends on your symptoms, how you react to the drug, and whether you can tolerate drowsiness. If you’ve used loratadine before pregnancy and it worked well, there’s no reason to switch.

What to Avoid - Especially in the First Trimester

Some medications are off-limits, and one of the biggest is pseudoephedrine. It’s the decongestant in many cold and allergy combos like Sudafed.

The ACOG says do not use pseudoephedrine in the first trimester. Studies show a small but real increase in abdominal wall defects - like gastroschisis - when it’s taken early in pregnancy. Even if you’re just taking it for a few days, the risk is there.

After the first trimester? It might be okay for some women without high blood pressure, but only under a doctor’s supervision. The Mayo Clinic says if you must use it, stick to 30-60 mg every 4-6 hours, no more than 240 mg a day. But even then, avoid it if you can.

Also avoid combination products that include pseudoephedrine, dextromethorphan, or phenylephrine unless your doctor specifically approves them. Many OTC allergy pills mix antihistamines with decongestants - read the label carefully.

When to Try Something Else - Nasal Sprays and Non-Medication Options

Sometimes, you don’t need pills at all.

Corticosteroid nasal sprays like budesonide (Rhinocort), fluticasone (Flonase), and mometasone (Nasonex) are often more effective than oral antihistamines for nasal symptoms. And here’s the kicker: they’re considered safe in all trimesters. Why? Because they act locally. Very little enters your bloodstream, so even less reaches the baby.

For itchy skin or eczema, topical treatments like moisturizers, oatmeal baths, and low-strength hydrocortisone cream can help without any systemic exposure.

Non-drug strategies matter too:

• Use a saline nasal rinse (neti pot or squeeze bottle) daily to clear allergens.
• Keep windows closed during high pollen seasons.
• Wash bedding in hot water weekly to kill dust mites.
• Use HEPA filters in your bedroom.
• Try wearing sunglasses outside to block pollen from your eyes.

These won’t fix everything, but they reduce how much medicine you need.

How to Decide What’s Right for You

There’s no one-size-fits-all answer. Here’s how to think about it:

1. How bad are your symptoms? If you’re just sneezing once in a while, try non-drug methods first. If you’re waking up gasping for air or can’t eat, you need treatment.
2. What’s your history? Did you take loratadine before and it worked? Stick with it. Did diphenhydramine make you too groggy? Skip it.
3. Which trimester are you in? First trimester? Stick to the most proven options: chlorpheniramine, loratadine, cetirizine. Avoid anything new or untested.
4. Are you on other meds? Some antihistamines interact with prenatal vitamins or antidepressants. Talk to your doctor.

Always check with your OB-GYN or midwife before starting anything - even if it’s “just” an over-the-counter pill. They know your history, your risks, and what’s safest for you.

What About Long-Term Effects?

You might wonder: “Will this affect my child later?”

Right now, there’s no solid evidence that antihistamines taken during pregnancy cause learning problems, behavioral issues, or developmental delays. But long-term studies are still limited. Most research only looks at birth defects - not how kids grow up.

That’s why experts recommend using the lowest effective dose for the shortest time needed. If you only need one pill a week for hay fever, don’t take it every day. If your symptoms are worse in spring, stop after the season ends.

Future research will focus on newer antihistamines like levocetirizine and desloratadine - but for now, we don’t have enough data to recommend them over the older, better-studied options.

Bottom Line: You Don’t Have to Suffer

Pregnancy isn’t the time to tough it out. Allergies can be exhausting, painful, and stressful - and stress affects your baby just as much as a sneeze does.

The safest approach? Start with non-drug fixes. If those aren’t enough, talk to your doctor about loratadine or cetirizine. If you need something stronger, chlorpheniramine is a solid, well-tested option. Avoid decongestants like pseudoephedrine, especially early on.

And remember - your doctor isn’t judging you for wanting relief. They’ve seen this before. They want you to feel better. The goal isn’t to avoid all medication. It’s to choose the right one, at the right time, in the right dose.

With the right plan, you can breathe easy - and so can your baby.