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 popping an over-the-counter antihistamine? That’s not so simple. You’re not just thinking about yourself anymore. You’re thinking about your baby. The truth is, antihistamines in pregnancy aren’t a simple yes-or-no question. Some are considered safe. Others come with warnings. And some? You should avoid them entirely.

What Are Antihistamines, and Why Do Pregnant Women Need Them?

Antihistamines block histamine, the chemical your body releases during an allergic reaction. That’s why they help with sneezing, runny nose, itchy eyes, and hives. For many pregnant women, allergies get worse during pregnancy. Hormones change how your immune system reacts. You might develop new allergies, or your old ones might flare up. Untreated, these symptoms can mess with your sleep, your appetite, and your mental health. Severe allergic rhinitis can even make asthma harder to control - which puts both you and your baby at risk.

So, it’s not about avoiding meds at all costs. It’s about choosing the right ones.

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

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

First-generation antihistamines - like chlorpheniramine (ChlorTrimeton), diphenhydramine (Benadryl), and dexchlorpheniramine - cross into your brain. That’s why they make you sleepy. They’ve been around for decades. Diphenhydramine has been used since the 1940s. Chlorpheniramine since the 1950s. That means there’s a ton of data. Studies tracking thousands of pregnancies show no clear link between these drugs and birth defects. The American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Family Physicians (AAFP) both say they’re safe to use.

But here’s the catch: drowsiness. If you’re already tired from pregnancy, adding a sedating antihistamine might make it worse. It can affect your ability to drive, work, or care for other kids. And if you’re taking it every day, that constant sleepiness isn’t just annoying - it can lower your quality of life.

Second-generation antihistamines - like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) - don’t cross the blood-brain barrier as much. That means little to no drowsiness. They’re the go-to for most people outside of pregnancy. But during pregnancy, the data isn’t as old. They haven’t been around as long, so there’s less long-term tracking.

Still, what we do know is reassuring. Large studies, including data from the National Birth Defects Prevention Study, haven’t found a consistent pattern of birth defects linked to loratadine or cetirizine. The Mayo Clinic, ACOG, and the American College of Allergy, Asthma & Immunology (ACAAI) all say these are safe options for mild to moderate symptoms. In fact, they’re often the first choice now - because they work just as well without the sleepiness.

What Do the Experts Recommend?

Let’s cut through the noise. Here’s what the top medical groups agree on in 2026:

• First-line oral antihistamines for mild symptoms: Loratadine (Claritin) and cetirizine (Zyrtec). These are non-sedating, well-studied, and widely recommended.
• Alternative if those don’t work: Chlorpheniramine. It’s sedating, but has decades of safety data. If you’re okay with the drowsiness, it’s a solid backup.
• For moderate to severe symptoms: Combine a steroid nasal spray (like budesonide, fluticasone, or mometasone) with one of the above antihistamines. Nasal sprays are even safer than oral meds - they don’t enter your bloodstream much at all. ACOG and AAFP both give them a safety rating of B, meaning benefits outweigh risks.

Hydroxyzine (Atarax) is sometimes used for itching, especially in eczema or hives. But it’s a first-generation antihistamine with a red flag: a few small studies have linked it to a slightly higher chance of certain heart defects in babies. The CDC’s data shows only seven cases total, but because the risk isn’t zero, most doctors avoid it unless there’s no other option.

What to Avoid Completely

There’s one drug you should never take in the first trimester: pseudoephedrine. It’s a decongestant, often paired with antihistamines in cold and allergy meds like Sudafed or Claritin-D. Pseudoephedrine has been linked to a rare but serious birth defect called gastroschisis - where the baby’s intestines develop outside the abdomen. The risk is small, but real. ACOG says avoid it entirely in the first 3 months. Even if you’re tempted to grab a combo pill, check the label. Many OTC allergy meds include pseudoephedrine.

Second-trimester use? Maybe. Mayo Clinic says it can be used after the first trimester at low doses (30-60 mg every 4-6 hours, max 240 mg daily) - but only if you don’t have high blood pressure. Still, many doctors skip it entirely and stick with nasal sprays instead.

Also avoid phenylephrine - another common decongestant. It’s in many cold meds, but there’s even less safety data than pseudoephedrine. Skip it.

What About Natural Remedies?

Some women turn to saline nasal rinses, humidifiers, or honey for relief. These are safe and often helpful. Saline sprays can clear nasal passages without any drug risk. Using a neti pot with distilled water? Also fine. Air purifiers can reduce allergens in your home. Avoid herbal supplements unless your doctor approves them. Many aren’t tested in pregnancy - and some can be harmful.

Don’t assume “natural” means safe. Butterbur, for example, is sometimes used for allergies, but it can contain liver-toxic compounds. Stick with what’s proven.

How to Use Antihistamines Safely During Pregnancy

Even safe meds need smart use. Here’s how to minimize risk:

1. Start with the lowest dose. If one tablet of loratadine (10 mg) helps, don’t take two.
2. Use only when needed. If your symptoms are mild and seasonal, try avoiding triggers first - like staying indoors on high-pollen days, washing your hair before bed, or using allergen-proof bedding.
3. Don’t combine meds without checking. Many OTC products mix antihistamines with decongestants or pain relievers. Read labels carefully. You might be taking more than you think.
4. Talk to your OB or allergist before starting anything. Even if it’s “just” Zyrtec. Your doctor knows your history, your symptoms, and your risks. They can help you pick the safest option.

What If My Allergies Are Severe?

If you have asthma, chronic hives, or severe rhinitis, not treating it can be more dangerous than treating it. Uncontrolled asthma increases the risk of preterm birth and low birth weight. Constant itching from eczema can lead to infections or sleep deprivation that affects your mood and nutrition.

In these cases, treatment isn’t optional - it’s necessary. Your doctor might recommend:

• High-dose steroid nasal sprays (safe all trimesters)
• Antihistamines like cetirizine or loratadine at standard doses
• Immunotherapy (allergy shots) - if you were already on them before pregnancy, you can usually continue
• Referral to an allergist for a personalized plan

Don’t suffer silently. Your health matters - and it directly affects your baby’s.

Final Thoughts: It’s About Balance

There’s no such thing as a 100% risk-free medication in pregnancy. But there are plenty of options with strong safety data. The goal isn’t to avoid all drugs. It’s to avoid unnecessary risk - while still protecting your health.

Loratadine and cetirizine are your best bets for daily relief. Chlorpheniramine is a trusted backup if you need something stronger and don’t mind the sleepiness. Steroid nasal sprays are often even safer than pills. Avoid pseudoephedrine in the first trimester. And always, always check with your provider before taking anything new.

Having allergies during pregnancy doesn’t mean you have to live in discomfort. With the right info and the right meds, you can breathe easier - and sleep better - without putting your baby at risk.