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

Managing Allergies During Pregnancy Isn’t Optional - It’s Necessary

If you’re pregnant and dealing with sneezing, itchy eyes, or a runny nose that won’t quit, you’re not alone. About 20% of pregnant women experience worsened allergies or new-onset allergic rhinitis during pregnancy. But here’s the real question: can you take antihistamines safely - and if so, which ones?

The answer isn’t simple. Some antihistamines have been used for decades with no clear link to birth defects. Others have less data, but what’s out there is mostly reassuring. The key isn’t avoiding all medication - it’s choosing the right one at the right time.

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

Not all antihistamines are the same. They’re split into two groups based on how they affect your brain.

First-generation antihistamines - like chlorpheniramine (ChlorTrimeton) and diphenhydramine (Benadryl) - cross the blood-brain barrier. That’s why they make you drowsy. They’ve been around since the 1940s and 1950s. Millions of pregnant women have taken them. Studies tracking birth outcomes show no consistent pattern of birth defects. The American College of Obstetricians and Gynecologists (ACOG) lists chlorpheniramine as a safe option.

Second-generation antihistamines - like loratadine (Claritin) and cetirizine (Zyrtec) - don’t cause drowsiness because they barely enter the brain. They’re newer, so there’s less long-term data, but the evidence we have is strong. A large CDC study of over 10,000 pregnancies found no increased risk of major birth defects with loratadine or cetirizine. The Mayo Clinic and the American College of Allergy, Asthma & Immunology both recommend these as first-line choices for mild symptoms.

Which Antihistamines Are Safest in Pregnancy?

Based on decades of use and recent studies, these three are the most trusted:

• Chlorpheniramine - The oldest, most studied. Safe in all trimesters. Side effect? Drowsiness. Best taken at night.
• Loratadine - Non-sedating. Taken once daily. No increased risk of heart defects, cleft palate, or other major issues in multiple studies.
• Cetirizine - Also non-sedating for most people. Data from over 1,500 pregnancies show no safety red flags.

These are the ones your OB-GYN or allergist will likely suggest first. They’re available over the counter, but don’t assume that means they’re risk-free. Always check with your provider before starting anything.

What About the Newer Ones? Fexofenadine, Levocetirizine, Desloratadine

Fexofenadine (Allegra), levocetirizine (Xyzal), and desloratadine (Clarinex) are newer second-generation options. They’re marketed as even less sedating, but pregnancy data is limited. A few small studies haven’t raised alarms, but they’re not yet recommended as first-line choices. If your doctor prescribes one, it’s likely because you’ve tried the others and they didn’t work.

Don’t self-experiment. These aren’t proven safer - just newer. Stick with the well-studied options unless your provider says otherwise.

The Big Red Flag: Pseudoephedrine and Decongestants

Many allergy meds combine antihistamines with decongestants like pseudoephedrine. That’s where things get risky.

Pseudoephedrine - found in Sudafed and many multi-symptom cold/allergy pills - has been linked to a small but real increase in abdominal wall defects (like gastroschisis) when taken during the first trimester. The ACOG says avoid it entirely in the first 12 weeks. After that, it may be considered at low doses (30-60 mg every 4-6 hours, max 240 mg/day) if you have severe congestion and no high blood pressure.

Always read labels. If a product says “sinus relief,” “cold + flu,” or “allergy + congestion,” it likely contains pseudoephedrine or phenylephrine. Skip them unless your doctor says yes.

Nasal Sprays: A Better Option for Moderate to Severe Symptoms

If antihistamines alone aren’t enough, nasal sprays are often the next step - and they’re safer than oral meds.

Corticosteroid sprays like budesonide (Rhinocort), fluticasone (Flonase), and mometasone (Nasonex) are considered safe in all trimesters. They work locally in the nose, so very little enters your bloodstream. The American Academy of Family Physicians rates them as safe (evidence rating B), and the Mayo Clinic recommends them for moderate to severe allergic rhinitis.

Use them daily, not just when symptoms flare. It takes a few days to build up full effect. And don’t use them with decongestant sprays (like oxymetazoline) - those can cause rebound congestion and aren’t recommended during pregnancy.

When Should You Skip Antihistamines Altogether?

You don’t need medication for every sniffle. Mild symptoms can often be managed with:

• Saline nasal rinses
• Keeping windows closed during high pollen seasons
• Using HEPA filters at home
• Washing bedding weekly in hot water
• Showering after being outside

But if your allergies are keeping you awake, stopping you from eating, or making you anxious - that’s when treatment becomes necessary. Untreated severe rhinitis can lead to sinus infections or worsen asthma. And uncontrolled asthma during pregnancy carries far greater risks than taking a safe antihistamine.

What About Natural Remedies or Herbal Supplements?

Don’t assume “natural” means safe. Butterbur, stinging nettle, and quercetin are sometimes promoted for allergies, but there’s no solid safety data for them in pregnancy. Some herbs can stimulate uterine contractions or interfere with hormone levels.

The American College of Obstetricians and Gynecologists explicitly advises against using herbal supplements without medical approval. Stick to what’s been studied - not what’s trendy.

What to Do If You Took an Antihistamine Before Knowing You Were Pregnant

If you took diphenhydramine or loratadine in the first few weeks before you knew you were pregnant, don’t panic. The critical window for major birth defects is between weeks 3 and 8. Most antihistamines don’t cause harm even if taken then.

Studies show no increased risk of malformations from early exposure to chlorpheniramine, loratadine, or cetirizine. The key is to stop taking anything unnecessary going forward and talk to your provider. They’ll likely just monitor your pregnancy normally.

Bottom Line: Your Best Moves

• For mild symptoms: Try loratadine or cetirizine first. They’re non-sedating and well-studied.
• If you need something stronger: Add a corticosteroid nasal spray like fluticasone.
• For nighttime relief: Chlorpheniramine is okay, but expect drowsiness.
• Avoid: Any product with pseudoephedrine or phenylephrine in the first trimester.
• Never: Take herbal supplements or combination cold/allergy pills without checking with your doctor.

The goal isn’t to live without medication. It’s to live well - without risking your baby’s health. If your allergies are controlling your life, talk to your OB-GYN or an allergist. There’s a safe, effective option out there for you.

What to Do Next

If you’re pregnant and struggling with allergies, don’t suffer in silence. Talk to your OB-GYN or a board-certified allergist. Bring a list of everything you’ve taken - even over-the-counter stuff. They’ll help you match your symptoms with the safest, most effective treatment.

And remember: managing your allergies isn’t selfish - it’s essential. Better sleep, better breathing, and less stress mean a healthier pregnancy for you and your baby.