Asthma and Pregnancy: Managing Symptoms and Medication Safely

Medically reviewed | Florida Asthma Clinic | Updated August 2026

Asthma is one of the most common chronic conditions to complicate pregnancy, affecting an estimated 4 to 8 percent of pregnant women in the United States. For many expecting mothers, the biggest source of anxiety is not the asthma itself but whether it is safe to keep using their medication. The clinical consensus is clear on this point: well-controlled asthma, maintained with appropriate medication, is markedly safer for both mother and baby than asthma that is left untreated out of fear of the medication.

How Pregnancy Affects Asthma

Pregnancy changes the body in ways that can shift asthma control in either direction. Rising progesterone increases respiratory drive, the growing uterus reduces lung capacity by elevating the diaphragm, and immune changes can alter sensitivity to allergens and triggers. Clinical studies generally describe a "rule of thirds": roughly a third of pregnant patients see their asthma worsen, a third see improvement, and a third notice little change. Symptoms most commonly shift during weeks 24 to 36, with many patients experiencing more stability again in the final weeks before delivery and during labor itself.

Because the pattern is unpredictable, the safest approach is to monitor closely rather than assume your asthma will behave the same way it did before pregnancy or during a previous pregnancy.

Why Untreated Asthma Is Riskier Than Asthma Medication

It is a common instinct to want to minimize any medication during pregnancy, but with asthma this instinct can backfire. When asthma is poorly controlled, oxygen levels in the mother's blood can drop during flare-ups, reducing oxygen delivery to the placenta. Research has linked poorly controlled asthma during pregnancy to a higher risk of:

• Preeclampsia (high blood pressure during pregnancy)
• Preterm birth and low birth weight
• Intrauterine growth restriction
• Gestational diabetes
• Increased need for cesarean delivery

These risks are consistently associated with uncontrolled symptoms — not with appropriate use of standard asthma medication. Major medical bodies, including the American College of Obstetricians and Gynecologists, recommend continuing asthma treatment through pregnancy for this reason.

Which Asthma Medications Are Considered Safe During Pregnancy

Rescue Inhalers

Albuterol is the preferred short-acting rescue medication during pregnancy. Decades of use and observational data have not shown an increased risk of birth defects, and it remains the first-line choice for quick symptom relief.

Inhaled Corticosteroids

Inhaled corticosteroids are the backbone of controller therapy in pregnancy, just as they are outside of it. Budesonide has the largest safety dataset in pregnancy, but guidelines generally support continuing whichever inhaled corticosteroid was already controlling your asthma well rather than switching medications unnecessarily.

Long-Acting Bronchodilators and Combination Inhalers

Combination inhalers pairing an inhaled corticosteroid with a long-acting beta-agonist (LABA) are typically continued in patients who needed them for control before pregnancy. Stopping a working combination inhaler is more likely to trigger a flare than to protect the pregnancy.

Leukotriene Modifiers and Biologics

Montelukast is generally considered an option for patients who needed it for control before becoming pregnant. Biologic medications for severe asthma have more limited pregnancy safety data; some, like omalizumab, have reassuring registry data, while decisions about others should be made individually with a specialist, weighing the risk of severe uncontrolled asthma against the specific biologic in question.

Medications That Need Extra Caution

Oral systemic corticosteroids (such as prednisone) are sometimes necessary for severe flare-ups and are used when the benefit outweighs the risk, but they are reserved for short courses rather than routine daily use. Decongestants containing pseudoephedrine are generally avoided in the first trimester. Aspirin and NSAIDs should already be avoided by anyone with aspirin-sensitive asthma, and are also generally limited in later pregnancy for obstetric reasons — always review your full medication list, including over-the-counter cold and allergy products, with your care team.

Monitoring Asthma Control During Pregnancy

Because control can shift quickly, most asthma specialists recommend more frequent check-ins during pregnancy than usual, including:

• Monthly asthma control assessments, or more often if symptoms are unstable
• Continued use of a peak flow meter if you used one before pregnancy, to track your personal best against pregnancy readings
• Spirometry testing if there is any uncertainty about control
• Coordination between your obstetrician and your asthma or pulmonology specialist, rather than seeing each in isolation

Fetal growth is often monitored more closely in pregnancies affected by moderate to severe asthma, including additional ultrasounds in the third trimester to confirm the baby is growing on track.

Labor, Delivery and Postpartum Care

Asthma attacks during labor itself are uncommon, and most patients continue their regular controller medications right up to delivery. If a cesarean delivery is needed, anesthesiologists are typically informed of an asthma diagnosis in advance, since certain medications used during labor and delivery (including specific prostaglandins sometimes used to manage bleeding) can trigger bronchospasm in asthma patients and are avoided or used cautiously.

After delivery, most standard asthma medications — including inhaled corticosteroids, combination inhalers and albuterol — are considered compatible with breastfeeding, since only a small amount transfers into breast milk. It is still worth confirming your specific medication list with your doctor after birth, and postpartum hormonal shifts mean it is worth continuing to monitor symptoms closely rather than assuming control will stay the same as it was late in pregnancy.

Warning Signs to Report Immediately

Practical Tips for Expecting Mothers With Asthma

• Keep taking your prescribed controller medication unless your doctor specifically tells you to stop
• Bring your full medication list to every prenatal visit, not just your asthma appointments
• Avoid known triggers more strictly than usual, since even a mild flare can feel more taxing on a body already working harder to breathe
• Get a flu vaccine during pregnancy, since respiratory infections can significantly worsen asthma and pose additional risk during pregnancy
• Ask about a written asthma action plan updated specifically for pregnancy, including when to call your obstetrician versus your asthma specialist
• Attend every scheduled prenatal visit, even if you feel your asthma is well controlled

Frequently Asked Questions