Asthma in Pregnancy

The Effects of Your Condition and Its Treatment

If you have asthma and are pregnant or want to conceive, you may worry about how your asthma might impact your pregnancy and baby.

About 3% to 8% of pregnant people have preexisting asthma. While some research shows asthma can cause pregnancy complications, it rarely poses a significant risk during pregnancy when it is properly treated.

You can increase your chance for a healthy pregnancy by:

  • Understanding guidelines for using asthma medications during pregnancy
  • Following your treatment plan for managing asthma
  • Knowing how to watch for potential complications

This article explains the symptoms, complications, diagnosis, and treatment of asthma during pregnancy.

Risks of Poorly Controlled Asthma in Pregnancy

Verywell / Theresa Chiechi

Symptoms of Asthma in Pregnancy

During pregnancy, you're likely to have the same asthma symptoms that you've had previously. Symptoms may include:

However, you may experience these to a greater or lesser extent than you did before conceiving. For example:

  • Approximately 33% of pregnant people with asthma have more severe symptoms during pregnancy.
  • Others feel the same or notice that their symptoms become milder.
  • When asthma does worsen, symptoms typically become most serious between 29 and 36 weeks gestation. Symptoms usually become less severe in weeks 36 to 40.

Don't assume that any breathing changes you are experiencing result from weight gain or pressure from your baby. Wheezing, for instance, is never a pregnancy-related symptom.

Risks and Complications

To help prevent asthma-related complications, be sure to follow your treatment plan and talk to your healthcare provider about any changes in your symptoms.

Most problems involving asthma during pregnancy are the result of inadequately treating the asthma. These problems can affect both you and your baby.

Pregnancy Complications

Poorly controlled asthma can lead to complications with your pregnancy. These complications may include:

Sometimes, one complication can lead to others. For example, preeclampsia increases the risk of preterm birth and placental abruption. Therefore, it should be monitored for and managed carefully.

Even if your asthma gets worse during pregnancy, it doesn't appear to increase your risk of a severe asthma attack during childbirth. In fact, asthma usually improves during labor and delivery.

Fetal Complications

Asthma attacks can lower blood flow and oxygen to your baby. This can lead to complications before and after birth and even cause life-long health issues. Possible fetal complications include:

Uncontrolled asthma during pregnancy may increase the risk of infant death, premature delivery, or low birth weight by between 15% and 20%.

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Your healthcare provider may newly diagnose you with asthma during your pregnancy. But often, when that happens, the condition wasn't new; it had just gone undiagnosed.

Asthma is not brought on by pregnancy or body changes associated with pregnancy.

If you've never had asthma before and have new breathing problems during pregnancy, talk to your healthcare provider right away. People newly diagnosed with asthma during pregnancy are 2.7 times more likely to experience asthma attacks, including hospitalization.

To determine whether you have asthma, your healthcare provider will:

  1. Examine you: They will look for common asthma symptoms, including wheezing, cough, chest tightness, and shortness of breath.
  2. Measure airflow in your lungs: This will help determine whether decreased airflow improves spontaneously or with treatment.

Monitoring Existing Asthma

If your asthma symptoms seem to be worsening, discuss them with your obstetrician, allergist, and pulmonologist.

Pregnancy can affect breathing to some degree. So your healthcare provider may perform spirometry, a pulmonary function test.

This will help your healthcare provider determine whether your symptoms are normal pregnancy-related issues or worsening asthma. Tests will focus on vital and total lung capacity, which are not usually affected during pregnancy.


Asthma treatment involves two things—avoiding triggers and managing symptoms.


The first course of asthma treatment for pregnant people is to avoid triggers that cause the immune system to overreact and spark an asthma attack. The most common triggers are:

Managing Symptoms

The next step is to control symptoms with medication. In general, healthcare providers aren't likely to prescribe a different asthma medication during pregnancy. Rather, your asthma plan will probably include the same drugs you used before pregnancy unless there's a compelling reason to switch.

Some people avoid taking asthma medications during pregnancy for fear that they may harm the baby. This can lead to asthma symptoms worsening. But asthma itself is a greater risk to fetal development than the side effects of asthma medications.

Medication Risks During Pregnancy

A long-term study found that asthma medication use during pregnancy doesn't raise the risk of most birth defects. However, researchers say it might increase the risk of some, including:

  • Atresia: Lack of a proper opening in the esophagus or anus
  • Omphalocele: Internal organs protruding through the belly button

However, the research did not conclude whether the birth defects were related to medication use, asthma itself, or a different medical condition.

Even if the medications are to blame, the risks of uncontrolled asthma still appear to be higher than the risks of most asthma medications.

For this reason, in a study published in 2020, researchers recommended an electronic system to reduce the risk of uncontrolled asthma during pregnancy. The system notifies healthcare providers when pregnant patients with asthma go more than four months without filling a prescription.

 Drug Class Drug Use in Pregnancy 
Short-acting beta-agonists (SABAs) terbutaline Preferred; controversial when used alone
Preferred; controversial when used alone
Long-acting beta-agonists (LABAs) formoterol
Inhaled corticosteroids (ICSs) budesonide First-line treatment (preferred over other ICSs)
Preferred, first-line treatment
With caution
Oral corticosteroids methylprednisolone
With caution
ICS+ LABA budesonide/fomoterol
Leukotriene modifiers montelukast
Preferred when started pre-pregnancy
  zileuton With caution due to liver side effects
Anticholinergics ipratropium Preferred as add-on for severe attacks
Anti-IgE medications (monoclonal antibodies) omalizumab With caution; shouldn't be started during pregnancy
Methylxanthines theophylline With caution
Mast-cell stabilizers cromolyn With caution
Source: Prescribers' Digital Reference

Preferred Medications

Most healthcare providers recommend inhaled asthma medications during pregnancy. That's because they target the source of asthma symptoms and very little medication crosses the placenta. In addition, several classes of medications are considered safe during pregnancy, at least in some circumstances.

Inhaled corticosteroids are considered the first-line treatment and are most often used during pregnancy, followed by beta2-agonists.

Inhaled Corticosteroids (ICS)

While studies are unclear on whether the inhaled form of these drugs increases the risk of birth defects, there has been some suggestion that they may increase the risk of cleft lip or palate.

On the other hand, research shows the risk of low birth weight is higher in those with asthma who don't take these drugs during pregnancy. But not all drugs in this category are considered safe during pregnancy.


These include SABAs and LABAs. Some controversy exists about their safety during pregnancy. For example, albuterol is considered the safest SABA, and salmeterol is considered the safest LABA.

Some experts argue against using SABAs alone during pregnancy. That's because they don't prevent asthma attacks. which can put your baby in danger.

Other Preferred Drugs

Many other drugs may be continued during your pregnancy, but they may not be the best option for everyone. These include:

  • Anticholinergics: While these drugs appear safe during pregnancy, little research has been done.
  • Theophylline and cromolyn: No association between these drugs and birth defects has been found. However, they may cause unpleasant side effects and interact negatively with other medications.
  • Leukotriene receptor agonists (LTRAs): These drugs are only recommended if you took them before getting pregnant. An exception is zileuton, which isn't recommended during pregnancy because of liver-related side effects.
  • Allergen immunotherapy (AIT): This treatment can often be continued during pregnancy. It's not clear whether it's safe to start it during pregnancy, though.

Non-Preferred Medications

Some inhaled corticosteroids cross the placenta in high concentrations and pose a risk.

Corticosteroids not recommended during pregnancy include dexamethasone, betamethasone, and oral prednisone because they're associated with higher rates of birth defects.

Omalizumab shouldn't be started during pregnancy because the dosage is weight-dependent. This presents a problem with the rapid weight gain of pregnancy.

Does Your Treatment Need a Change?

Your asthma is considered poorly controlled if your asthma symptoms:

  • Are present more than two days per week
  • Wake you up more than two nights per month

Uncontrolled asthma places your baby at risk for reduced oxygen and associated problems. Talk to your healthcare providers about adjusting your treatment plan so you can properly manage the condition.


Well-controlled asthma rarely causes problems during pregnancy. However, poorly controlled asthma can lead to risks both for the mother and baby, including high blood pressure, complicated labor, low birth weight, birth defects, and death.

It's important to follow your treatment plan closely during pregnancy and tell your healthcare provider if your symptoms are worsening or you have new breathing problems. Some asthma medications have risks in pregnancy, but the risks are generally less than skipping treatment.

A Word From Verywell

About one-third of people with asthma who get pregnant will have more severe symptoms during pregnancy. Another third will experience less severe symptoms. The final third will have no change in symptoms.

You can't be sure where you'll fall in this mix, so you must continue to see your asthma specialist throughout your pregnancy. Having your asthma monitored and following your treatment plan is always important, but especially so during pregnancy.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.