Allergies, Asthma, and Pregnancy: What You Actually Need to Know

I recently joined my friend and colleague Dr. Erica Bove on her podcast, Love and Science Fertility, to talk about something that doesn’t get enough attention:

How to manage allergies and asthma when you’re trying to conceive or already pregnant.

This is one of the most common concerns I hear in my office. Women will ask:

Should I stop my inhaler?
Are antihistamines safe?
What about my allergy shots?
Will my asthma affect the baby?

And often, they’re nervous. Understandably.

So let’s walk through this calmly and practically.

Why Asthma Control Is Critical During Pregnancy

Here’s the message I want you to remember:

Well-controlled asthma is safer than poorly controlled asthma during pregnancy.

When asthma is uncontrolled, oxygen levels can drop. Pregnancy increases oxygen demand — for both mom and baby. Poor asthma control has been associated with preterm delivery and low birth weight.

Stopping inhalers out of fear is usually not the right move.

If your asthma is stable on your current medications, staying stable is typically the safest course.

Safe Allergy Medications in Pregnancy

Antihistamines That Are Commonly Recommended

Let’s simplify this.

For antihistamines, the two most studied and commonly recommended options in pregnancy are:

Loratadine (Claritin)
Cetirizine (Zyrtec)

Both are non-drowsy and widely used.

Fexofenadine (Allegra) is also commonly used and tends to be less sedating.

Nasal Steroids and Why They Matter

Nasal steroids are still first-line therapy for allergic rhinitis — even in pregnancy.

Budesonide (Nasacort) has the strongest safety data in pregnancy. Fluticasone (Flonase) is also widely used and generally considered acceptable.

Nasal steroids help reduce inflammation, improve post-nasal drip, support better sleep, and indirectly improve asthma control.

What Allergy Medications Should Be Avoided?

Systemic decongestants like pseudoephedrine (Sudafed) are generally avoided in pregnancy unless specifically recommended.

Phenylephrine should also be avoided.

Decongestants can also reduce breast milk supply in the postpartum period.

Short-term use of topical oxymetazoline (Afrin) may be appropriate in select situations, but long-term use is not recommended without physician guidance.

Environmental Strategies That Help During Pregnancy

Sometimes simple environmental strategies make a big difference.

Dust Mite Prevention

If your symptoms are worse in the morning, dust mites may be contributing. We aren't allergic to the mites themselves, but we are allergic to their droppings! If your face is buried in dust mite droppings all night, you may be having symptoms. Here are some ways that you can clean up the mite droppings:

Washing bedding weekly in hot water
Using mattress encasements
Drying pillows on high heat
Keeping humidity low

Dust mites thrive in humidity, so humidifiers are not typically helpful for dust mite allergy.

HEPA Filters and Air Quality

Portable HEPA filters can reduce airborne allergens and improve overall air quality. I often recommend standalone units rather than relying solely on HVAC filters. However, dust mite droppings are heavier and are not necessarily improved by HEPA filters.

Managing Pet Allergies

If you’re allergic to pets:

Keep pets out of the bedroom
Bathe dogs weekly
Use HEPA filtration - these DEFINITELY help with pet allergy.

Small changes can significantly reduce exposure.

Can You Continue Allergy Shots During Pregnancy?

Allergy shots work by retraining the immune system over time.

If you are already on maintenance allergy shots and doing well, you can typically continue them during pregnancy.

However:

We do not start allergy shots during pregnancy.
We do not increase doses during pregnancy.

If you’re planning pregnancy and considering immunotherapy, it’s wise to start early enough to reach maintenance before conception.

Biologic Medications Like Xolair and Dupixent

Some patients are on medications such as omalizumab (Xolair) or dupilumab (Dupixent) for asthma, eczema, chronic hives, or nasal polyps.

Safety data for these medications during pregnancy is growing and generally reassuring. In many cases, continuing a biologic that is controlling severe disease is appropriate.

Again, stability is protective.

Progesterone Reactions During IVF and Fertility Treatments

We also discussed reactions to progesterone during IVF.

True endogenous progesterone allergy is very rare. More commonly, reactions occur to the carrier oils or additives in progesterone formulations.

For example, some progesterone products contain peanut oil. Others may include excipients that certain individuals react to.

In complex cases, allergists may consider testing, changing formulations, or, in rare cases, desensitization protocols. This requires individualized care and collaboration between specialties.

Does Maternal Diet Affect Baby’s Allergy Risk?

Current evidence does not support routinely avoiding allergenic foods during pregnancy to prevent allergies in the child.

We do know that poorly controlled maternal asthma is associated with worse outcomes.

We also know from studies like the LEAP peanut study that early introduction of allergenic foods around 4 to 6 months of age reduces food allergy risk.

Infants with eczema are at higher risk of food allergy because allergens can enter through a disrupted skin barrier.

I often explain it this way:

Through the skin, allergies begin.
Through the diet, they stay quiet.

Managing eczema well and introducing foods appropriately is more important than maternal food restriction during pregnancy.

The Bottom Line for Women Trying to Conceive

If you’re trying to conceive or are already pregnant:

Do not panic.
Do not abruptly stop medications.
Focus on control.
Work with a knowledgeable provider.

Pregnancy is not the time to “white-knuckle” your asthma or allergies.

Breathing well matters. Sleeping well matters. Oxygen matters.

If you’re in Florida and need support, you can learn more at https://www.cfma.health or call 727-446-1097.

Your health and your baby’s health are connected — and stability is powerful.

—
Dr. Kerry Reller
Board Certified Family Medicine and Obesity Medicine
Clearwater Family Medicine & Allergy

Frequently Asked Questions

Is it safe to use an asthma inhaler during pregnancy?

Yes. Well-controlled asthma is safer than poorly controlled asthma. Most maintenance inhalers are considered safe during pregnancy.

Can I take antihistamines while pregnant?

Loratadine (Claritin) and cetirizine (Zyrtec) are commonly recommended and widely studied in pregnancy.

Can I continue allergy shots during pregnancy?

If you are already on maintenance allergy shots, you can typically continue. New allergy shots are not started during pregnancy.

Should I stop allergy medications when trying to conceive?

No. Stability and control are more important than abruptly stopping medications.