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

When allergies strike during pregnancy, what can you actually take?

It’s 3 a.m. You’re wide awake, sneezing, eyes watering, nose stuffed up. Your pillow is soaked from post-nasal drip. You’ve tried saline sprays, humidifiers, even sleeping with your head propped up. Nothing helps. And now you’re wondering: is it safe to take an antihistamine while pregnant? You’re not alone. Up to 20% of pregnant women experience worsened allergies or new-onset allergic rhinitis during pregnancy. The truth? You don’t have to suffer - but not all antihistamines are created equal.

Some antihistamines have been used safely for decades. Others? We’re still learning. The goal isn’t to avoid all medication - it’s to pick the right one. Untreated allergies can hurt you too. Poor sleep, constant discomfort, and uncontrolled asthma raise your risk of preterm labor, low birth weight, and even preeclampsia. So the real question isn’t “Can I take it?” It’s “Which one is safest for me and my baby?”

First-generation vs. second-generation: What’s the difference?

Not all antihistamines are the same. They’re split into two groups: first-generation and second-generation. The difference isn’t just about brand names - it’s about how they work in your body.

First-generation antihistamines like chlorpheniramine (ChlorTrimeton) and diphenhydramine (Benadryl) cross the blood-brain barrier. That’s why they make you drowsy. They’re old - chlorpheniramine has been around since the 1950s, diphenhydramine since the 1940s. Because they’ve been used for so long, we have a ton of data. Multiple studies, including those reviewed by the American Academy of Family Physicians, show no increased risk of birth defects with these drugs. The ACOG confirms chlorpheniramine and dexchlorpheniramine are safe options during any trimester.

But here’s the catch: drowsiness. If you’re already tired from pregnancy hormones, adding a sedating antihistamine might make you feel like you’re dragging through molasses. That’s not just annoying - it can affect your ability to drive, work, or care for other kids. Plus, drowsiness doesn’t always mean it’s working better. It just means your brain is affected.

Second-generation antihistamines - like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) - were designed to avoid that brain hit. They barely cross into your central nervous system. That means little to no drowsiness. That’s a big win. But they’re newer. Less long-term data. Still, the evidence we do have is strong. A large CDC study tracking over 14 different antihistamines found no consistent link to birth defects. The American College of Allergy, Asthma & Immunology says both loratadine and cetirizine have “reassuring animal and human study data.”

What do doctors actually recommend?

Let’s cut through the noise. If you’re dealing with mild allergy symptoms - runny nose, itchy eyes, occasional sneezing - here’s what the top medical groups agree on:

• Loratadine (Claritin) - First choice. Minimal sedation, decades of safe use in pregnancy, low risk.
• Cetirizine (Zyrtec) - Almost as good. Slightly more likely to cause drowsiness than loratadine, but still far less than Benadryl. Safe in all trimesters.
• Chlorpheniramine - The old standby. Proven safe. Only downside? You’ll feel sleepy. Best for nighttime use if you can’t sleep.

The Mayo Clinic, ACOG, and AAFP all list these three as the safest oral options. No need to overcomplicate it. Start with loratadine. If it doesn’t help after a few days, try cetirizine. If you need something stronger at night, chlorpheniramine is fine - just don’t take it before driving or working.

For moderate to severe symptoms - think constant congestion, sinus pressure, or asthma flare-ups - nasal steroid sprays are often better than pills. Budesonide (Rhinocort), fluticasone (Flonase), and mometasone (Nasonex) are all rated as safe during pregnancy by the AAFP. They work right where the problem is - your nose - with almost no systemic absorption. That means less medicine in your bloodstream, and even less reaching your baby.

What antihistamines should you avoid?

Not all allergy meds are safe. Some are outright risky.

Hydroxyzine (Vistaril, Atarax) - This one’s a red flag. Studies have shown a possible link to certain birth defects, especially conotruncal heart defects. The CDC’s National Birth Defects Prevention Study flagged it based on limited but concerning data. Don’t take it unless your doctor has no other option.

Pseudoephedrine - This isn’t an antihistamine, but it’s often paired with them in cold/allergy combos like Sudafed. It’s a decongestant. And it’s dangerous in the first trimester. Research shows a small but real increase in abdominal wall defects like gastroschisis. The ACOG says avoid it entirely during the first 3 months. After that? Maybe, but only if you don’t have high blood pressure. Even then, use the lowest dose possible - no more than 60 mg every 4 to 6 hours, max 240 mg a day.

Dimenhydrinate (Dramamine) - Sometimes used for nausea, but it’s a first-gen antihistamine with strong sedative effects. Not ideal unless you’re dealing with severe motion sickness and nothing else works.

And please - skip combination products. “Allergy + decongestant” pills are a minefield. You’re getting two drugs, one of which (pseudoephedrine) you shouldn’t take early on. Always check the label. If it says “sinus,” “cold,” or “maximum strength,” walk away.

What about newer antihistamines like Xyzal or Clarinex?

Levocetirizine (Xyzal) and desloratadine (Clarinex) are the newer versions of cetirizine and loratadine. They’re more potent, but we don’t have as much data on them during pregnancy. No red flags yet - but no large, long-term studies either. Most doctors won’t recommend them as first-line unless you’ve tried the older ones and they didn’t work. If you’re already on one before pregnancy, talk to your OB. Don’t start one new during pregnancy unless absolutely necessary.

When should you call your doctor?

You don’t need to guess. If any of these apply, call your OB or allergist:

• Your symptoms are interfering with sleep, eating, or mood.
• You’ve tried loratadine or cetirizine and they’re not helping.
• You’re thinking about using a nasal spray or combination product.
• You have asthma or chronic sinus issues.
• You’re in your first trimester and considering any new medication.

ACOG’s message is clear: “Check with your ob-gyn before taking any over-the-counter allergy medication.” Even if it’s “just” Benadryl. The goal isn’t to scare you - it’s to make sure you’re not taking something that could do more harm than good.

Non-medication options: Can you manage without pills?

Yes - and you should try these first.

• Saline nasal rinses - Use a neti pot or squeeze bottle with distilled or boiled water. Clears mucus, reduces swelling, no side effects.
• HEPA air filters - Especially in your bedroom. Reduces pollen, dust mites, pet dander.
• Wash bedding weekly - Hot water kills dust mites. Use allergen-proof pillow and mattress covers.
• Shower before bed - Wash off pollen from hair and skin. Prevents nighttime flare-ups.
• Stay indoors on high-pollen days - Check local pollen counts. Keep windows closed.

These won’t cure allergies - but they can cut your symptoms by half. That means less need for meds. And if you still need something after trying these? Then you know you’re using medication because you need it - not because you’re desperate.

Final takeaway: Less is more, but don’t suffer

Pregnancy isn’t the time to experiment. Stick with the well-studied options: loratadine, cetirizine, chlorpheniramine. Avoid the risky ones: hydroxyzine, pseudoephedrine in the first trimester. Use nasal sprays if you need more help. And always talk to your doctor before starting anything.

Remember - your health matters too. If allergies are keeping you up, making you anxious, or triggering asthma, treating them isn’t dangerous. It’s necessary. The safest choice isn’t always the one with no drugs. Sometimes, it’s the one that lets you breathe, sleep, and feel like yourself again.