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

When you're pregnant and your nose is stuffed up, your eyes are itchy, or your skin is breaking out in hives, the last thing you want is to suffer through it. But the moment you reach for that bottle of Benadryl or Claritin, a question pops up: is this safe for my baby? You're not alone. Millions of pregnant people deal with allergies each year, and the fear of harming the baby often keeps them from treating symptoms at all. The truth? Some antihistamines are well-studied and considered safe. Others? Not so much. The key isn't avoiding all meds-it's choosing the right ones.

First-Generation vs. Second-Generation: What’s the Difference?

Not all antihistamines are created equal. They fall into two main groups: first-generation and second-generation. The difference isn’t just about how strong they are-it’s about how they affect your body.

First-generation antihistamines like chlorpheniramine (ChlorTrimeton), diphenhydramine (Benadryl), and dexchlorpheniramine cross the blood-brain barrier. That’s why they make you sleepy. They’ve been around for decades-Benadryl since 1946, chlorpheniramine since the 1950s. That long history means we have a ton of data on them during pregnancy. Studies involving thousands of pregnant women haven’t shown a clear link to birth defects. The American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Family Physicians (AAFP) both say these are safe options when needed.

But here’s the catch: drowsiness. If you’re already tired from pregnancy, adding a medication that knocks you out isn’t helpful. It can affect your ability to drive, care for other kids, or even get through your workday. That’s why many people look for alternatives.

Second-generation antihistamines like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) don’t cross the brain barrier as easily. That means less drowsiness. They’re newer, so we don’t have as many decades of data-but what we do have is reassuring. A large CDC study of over 1,400 pregnant women taking loratadine found no increase in birth defects. Cetirizine has similar results. ACOG’s March 2025 update says these newer options “may also be safe.”

What Do Experts Actually Recommend?

Major medical groups agree on one thing: treat severe symptoms. If your allergies are keeping you from sleeping, eating, or breathing properly, the risk of not treating them might be higher than the risk of the medication.

The Mayo Clinic, ACOG, and the American College of Allergy, Asthma & Immunology (ACAAI) all point to the same three as first-line choices:

• Loratadine (Claritin) - Non-sedating, minimal side effects, long safety track record in pregnancy
• Cetirizine (Zyrtec) - Also non-sedating for most people, though about 10% may feel slightly drowsy
• Chlorpheniramine - The most studied first-gen option, safe but sedating

These are the ones you’ll hear most often from OB-GYNs and allergists. If your symptoms are mild, start with one of these. If they’re worse-think constant congestion, sinus pressure, or asthma flares-your doctor might suggest a nasal steroid spray like budesonide (Rhinocort) or fluticasone (Flonase). These sprays work locally in your nose and don’t enter your bloodstream much, making them even safer than oral meds. AAFP gives them a safety rating of B, same as the top antihistamines.

What to Avoid: The Red Flags

Not all allergy meds are safe during pregnancy. Some have clear risks.

Pseudoephedrine (Sudafed) is the big one. It’s a decongestant often mixed with antihistamines in cold-and-allergy formulas. Studies show a small but real increase in abdominal wall defects-like gastroschisis-when taken during the first trimester. ACOG says: don’t use it in the first 3 months. If you’re past the first trimester and really need it, your doctor might consider it in low doses (30-60 mg every 4-6 hours), but only if you don’t have high blood pressure.

Hydroxyzine (Vistaril, Atarax) is another red flag. It’s sometimes used for severe itching or anxiety during pregnancy, but studies have linked it to a higher chance of conotruncal heart defects. One CDC analysis found only seven cases, but even small numbers matter when it comes to fetal development. Most doctors avoid it unless absolutely necessary.

And don’t assume “natural” means safe. Herbal remedies like butterbur or nettle leaf aren’t regulated, and their effects on pregnancy aren’t studied. Stick to what’s been tested.

Why the Confusion? Inconsistent Research

Why do some studies say one thing and others say the opposite? Because pregnancy research is hard. You can’t run controlled trials on pregnant women for ethical reasons. Most data comes from observational studies-tracking women who took meds and seeing what happened to their babies. These studies can miss small risks or get skewed by other factors like smoking, age, or underlying health conditions.

The CDC’s National Birth Defects Prevention Study looked at 14 different antihistamines and 64 types of birth defects. They found no major patterns overall, but some odd associations popped up-like a possible link between hydroxyzine and heart defects, or diphenhydramine and cleft palate. These were based on very small numbers. That doesn’t mean they’re dangerous-it means we need bigger studies.

That’s why experts go by the weight of evidence. When dozens of studies show no harm, and only a few hint at risk with tiny sample sizes, the safe choice is to trust the majority.

Practical Tips for Managing Allergies While Pregnant

Medication isn’t your only tool. Before reaching for a pill, try these non-drug strategies:

• Use a saline nasal spray or neti pot to flush out allergens
• Keep windows closed during high pollen seasons
• Wash your hair and change clothes after being outside
• Use HEPA filters in your bedroom
• Try wearing sunglasses outdoors to block pollen from your eyes

If you need medication:

1. Start with the lowest effective dose
2. Choose loratadine or cetirizine for daily use
3. Use chlorpheniramine only if you need sleep help and can plan for downtime
4. Combine a nasal steroid spray with an antihistamine if symptoms are moderate to severe
5. Never combine antihistamines with decongestants unless your doctor says so

And always, always talk to your OB-GYN before starting anything-even something you think is “just an OTC allergy pill.” They know your history, your risks, and your options.

What About Long-Term Effects?

So far, no major studies show that kids exposed to loratadine, cetirizine, or chlorpheniramine in the womb have developmental delays, learning issues, or behavioral problems later on. But long-term data is still limited. Most studies only track up to age 1 or 2. Researchers are now starting to follow these children into school age, but results aren’t in yet.

That doesn’t mean you should avoid meds. It means you should use them wisely. If you’re only taking one antihistamine occasionally during allergy season, the risk is extremely low. If you’re on multiple meds daily for chronic conditions like asthma or severe eczema, your doctor should monitor you more closely.

Final Takeaway: Don’t Suffer in Silence

Untreated allergies can hurt you and your baby. Poor sleep leads to stress. Constant congestion can trigger sinus infections or asthma attacks. If you’re too tired to eat, your baby isn’t getting the nutrients it needs. The goal isn’t to be medication-free-it’s to be smart about medication use.

Loratadine and cetirizine are your best bets for daily relief. Chlorpheniramine works too, but plan for the drowsiness. Avoid pseudoephedrine in the first trimester. Talk to your doctor. Use nasal sprays if you can. And remember: you’re not being reckless by treating your symptoms-you’re being responsible.