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 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 antihistamines on the shelf, doubt creeps in: Is this safe for my baby? You’re not alone. Thousands of pregnant people face this same question every year. The truth? Some antihistamines are considered safe. Others? Not so much. And the difference isn’t just about brand names-it’s about science, timing, and your specific symptoms.

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

Not all antihistamines are created equal. They fall into two main groups: first-generation and second-generation. The difference isn’t just marketing-it’s 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’ve been around for decades-chlorpheniramine since the 1950s, diphenhydramine since the 1940s. And because they’ve been used so long, we have a lot of data on them during pregnancy. Multiple studies, including those reviewed by the American Academy of Family Physicians, show no clear link between these drugs and birth defects. That’s why many doctors still recommend them as a first option.

But here’s the catch: the drowsiness isn’t just inconvenient. It can make driving dangerous, interfere with work, or leave you too tired to care for other kids. If you’re already dealing with pregnancy fatigue, adding sedation on top isn’t helpful.

Second-generation antihistamines like loratadine (Claritin) and cetirizine (Zyrtec) were designed to avoid that drowsiness. They don’t cross into the brain as easily. That’s why they’re called “non-sedating.” While they haven’t been around as long, the data we do have is reassuring. A large CDC study tracking over 14 different antihistamines and more than 60 types of birth defects found no consistent pattern of harm. The American College of Obstetricians and Gynecologists (ACOG) now says these newer options “may also be safe.”

What Do Experts Actually Recommend?

If you’re trying to decide what to take, you’re not looking for a one-size-fits-all answer. You need a personalized plan based on your symptoms and trimester.

For mild allergy symptoms-runny nose, itchy eyes-most experts agree: start with loratadine or cetirizine. These are the most commonly recommended oral antihistamines during pregnancy, according to the Mayo Clinic. They’re available over the counter, have minimal side effects, and have the strongest safety data among second-generation options.

If you need something stronger, chlorpheniramine remains a top choice among first-generation drugs. It’s not the most comfortable option because of drowsiness, but it’s the most studied. Many OB-GYNs will suggest it if you’ve tried loratadine and it didn’t help.

For nasal symptoms like congestion or post-nasal drip, nasal steroid sprays are often better than oral meds. Budesonide (Rhinocort), fluticasone (Flonase), and mometasone (Nasonex) are all considered safe in any trimester. They work locally in your nose, so very little enters your bloodstream. That means less risk for your baby-and fewer side effects for you.

What Antihistamines Should You Avoid?

Not all antihistamines are safe. Some have red flags.

Hydroxyzine (Atarax, Vistaril) is a first-generation antihistamine often used for anxiety and itching. But studies, including one from the CDC’s National Birth Defects Prevention Study, found a possible link to conotruncal heart defects when used in early pregnancy. The number of cases was small-only six exposed babies out of hundreds-but the signal is enough that most doctors avoid it unless absolutely necessary.

Also avoid promethazine (Phenergan), especially in the first trimester. While it’s sometimes used for nausea, it’s not a first-line allergy treatment, and its safety profile during pregnancy is less clear than chlorpheniramine or loratadine.

And don’t confuse antihistamines with decongestants. Pseudoephedrine (Sudafed) is not an antihistamine-it’s a decongestant. But it’s often sold in combination products. The ACOG says it should be avoided entirely in the first trimester because of a small but real risk of abdominal wall defects like gastroschisis. If you’re in your second or third trimester and have severe congestion, your doctor might allow it at low doses (30-60 mg every 4-6 hours, max 240 mg/day), but only if you don’t have high blood pressure.

When Is It Okay to Take Antihistamines?

You don’t need to suffer through allergies just because you’re pregnant. If your symptoms are affecting your sleep, your ability to eat, or your mental health, then treatment isn’t optional-it’s necessary.

Uncontrolled allergic rhinitis can lead to sinus infections, worsen asthma, and even affect your oxygen levels. That’s not good for you or your baby. A study from the American College of Allergy, Asthma & Immunology found that pregnant women with poorly controlled allergies were more likely to have complications like preterm birth or low birth weight-not because of the medication, but because of the inflammation and stress from the untreated condition.

So if you’re constantly sneezing, can’t sleep through the night, or your skin is breaking out in hives, talk to your doctor. The risk of doing nothing can be greater than the risk of taking a well-studied antihistamine.

Dosing and Timing Matter

Even safe medications need to be used wisely. Always take the lowest dose that works. Don’t double up because you think “more will help more.” That’s not true-and it increases your risk.

For loratadine: 10 mg once daily is the standard dose. For cetirizine: 10 mg once daily. For chlorpheniramine: 4 mg every 4 to 6 hours, not to exceed 24 mg in 24 hours.

Timing matters too. If you’re taking a sedating antihistamine like chlorpheniramine, take it at night. That way, the drowsiness helps you sleep instead of ruining your day.

And remember: just because it’s over the counter doesn’t mean it’s risk-free. Always check with your OB-GYN before starting any new medication, even if it’s sold on the shelf next to gum and candy.

What About Natural Remedies?

You might be tempted to try saline rinses, honey, or herbal teas instead. These can help with mild symptoms. Saline nasal sprays are safe and effective. A humidifier can ease congestion. But if your allergies are severe, natural remedies alone won’t cut it.

Some herbs and supplements can actually be harmful during pregnancy. For example, butterbur, sometimes used for allergies, has liver toxicity concerns and isn’t recommended. Always talk to your doctor before trying anything herbal.

What’s the Bottom Line?

There’s no perfect antihistamine for every pregnant person. But there are safe, well-studied options-and avoiding treatment can be riskier than using them.

• Start with loratadine or cetirizine for mild symptoms.
• If those don’t work, chlorpheniramine is a solid backup-take it at night.
• For nasal congestion, try a steroid spray like budesonide or fluticasone.
• Avoid hydroxyzine, promethazine, and pseudoephedrine in the first trimester.
• Always use the lowest effective dose.
• Never self-prescribe. Talk to your OB-GYN or allergist before starting anything.

Your allergies don’t have to control your pregnancy. With the right information and guidance, you can breathe easier-literally and figuratively.