Asthma During Pregnancy: Safe Treatment & Risks Canada

Asthma during pregnancy is more common than many Canadians realize, affecting up to 8% of expectant mothers across the country. It can impact your breathing, reduce your baby’s oxygen supply, and complicate your overall health if left uncontrolled. The reassuring news is that with proper care, most women with asthma deliver healthy babies.

How to Safely Manage Asthma During Pregnancy in Canada

Understanding asthma and pregnancy risks is the first step toward protecting yourself and your child. Whether you had asthma before conceiving or you are experiencing breathing problems for the first time, this guide covers the warning signs, safe treatment options approved in Canada, and practical steps to keep both you and your baby healthy throughout every trimester.

What Is Asthma During Pregnancy?

Treatment Options for Managing Asthma During Pregnancy

Treatment Option	Benefits	Considerations for Pregnant Patients
Inhaled Corticosteroids (e.g., budesonide)	First-line controller therapy; reduces airway inflammation and prevents flare-ups	Budesonide preferred; considered safe throughout pregnancy with most evidence supporting continued use
Short-Acting Beta-Agonists (e.g., salbutamol)	Rapid relief of acute symptoms; fast-acting bronchodilator for rescue use	Safe for use during pregnancy; frequent need may indicate poorly controlled asthma requiring reassessment
Long-Acting Beta-Agonists (e.g., salmeterol)	Provides extended bronchodilation; used alongside inhaled corticosteroids for moderate-to-severe asthma	Used only in combination with inhaled corticosteroids; not recommended as standalone therapy
Leukotriene Receptor Antagonists (e.g., montelukast)	Alternative add-on therapy for allergic asthma; reduces inflammation and allergic response	Generally considered when other treatments are insufficient; discuss risk-benefit with your healthcare provider
Oral Corticosteroids (e.g., prednisone)	Effective for managing severe asthma exacerbations when inhaled therapy is insufficient	Reserved for severe flare-ups; risks of prolonged use include gestational hypertension and preterm birth; use only as directed

Asthma is a chronic lung condition. It causes episodes of wheezing, shortness of breath, chest tightness, and coughing. Between episodes, lung function is usually normal.

Asthma is one of the most common medical conditions seen in pregnant women. Some women already have asthma before they become pregnant. Others develop breathing symptoms for the first time during pregnancy.

During pregnancy, uncontrolled asthma reduces the amount of oxygen reaching your baby. However, well-managed asthma during pregnancy carries a low risk to both mother and baby. The key word here is managed.

How Does Asthma Affect You and Your Baby?

When asthma during pregnancy is not properly controlled, it can lead to serious complications. These complications affect both the mother and the developing baby.

Risks to the Mother

Poorly controlled asthma can increase the risk of:

• High blood pressure during pregnancy (gestational hypertension)
• Preeclampsia — a serious condition involving high blood pressure, and damage to the kidneys, liver, and brain
• Severe morning sickness (hyperemesis gravidarum) — vomiting that is earlier and more intense than normal
• Complicated labour — labour may not start naturally and may need to be medically induced

Risks to the Baby

Uncontrolled asthma can also put your baby at risk. These risks include:

• Intrauterine growth restriction — the baby grows more slowly than expected and may appear small at birth
• Premature birth — delivery before 37 weeks of pregnancy
• Low birth weight
• In rare and severe cases, perinatal death (death around the time of birth)

The better your asthma is controlled, the lower these risks become. This is why treatment should never be stopped during pregnancy without talking to your doctor first.

How Asthma Symptoms Can Change During Pregnancy

Every pregnancy is different. About two-thirds of pregnant women notice a change in their asthma symptoms during pregnancy. Some women find their asthma improves. Others find it stays the same. Some find it gets worse.

Furthermore, new asthma symptoms can be easy to miss during pregnancy. Shortness of breath is common in pregnancy even without asthma. As a result, a new diagnosis can sometimes be delayed. If you notice wheezing, persistent coughing, or unusual breathlessness, speak to your family doctor or visit a walk-in clinic.

Your doctor will monitor your lung function throughout your pregnancy to track any changes. This is especially important because asthma severity can shift as your pregnancy progresses.

Safe Treatment Options for Asthma During Pregnancy

Many pregnant women worry about taking medication. However, research clearly shows that treating asthma during pregnancy is safer than leaving it uncontrolled. Poorly controlled asthma is more harmful to your baby than asthma medication.

According to Health Canada, managing chronic conditions during pregnancy is an important part of prenatal care. Your provincial health plan covers visits to your family doctor or obstetrician to help manage conditions like asthma.

Inhaled Corticosteroids

Inhaled corticosteroids are the most effective long-term treatment for asthma. They reduce airway inflammation. Used at the right dose, they are considered safe during pregnancy.

Reliever Inhalers (Rescue Inhalers)

Short-acting bronchodilators — often called reliever or rescue inhalers — are used during an asthma episode. These help open the airways quickly. They are generally considered safe to use during pregnancy.

Allergy Treatments

Many pregnant women also have allergic conditions, such as allergic rhinitis (hay fever). Treating allergies is an important part of managing asthma. Options that are generally considered safe during pregnancy include:

• Inhaled corticosteroids at the right dose
• Antihistamines such as loratadine or cetirizine
• Allergy immunotherapy shots — if you were already receiving these before pregnancy, they can usually be continued; however, they should not be started for the first time during pregnancy

In addition, talk to your doctor before using any oral decongestants. There may be safer alternatives that work just as well.

What About the Flu Shot?

Protecting yourself from influenza is especially important during pregnancy. The flu can trigger serious asthma episodes. The flu vaccine is safe at any stage of pregnancy. In Canada, it is recommended that all pregnant women get the flu shot before flu season begins — ideally in October or early November. Your family doctor, walk-in clinic, or local pharmacy can administer it. Your provincial health plan covers the flu shot for pregnant women in most provinces.

Monitoring Your Health and Your Baby’s Health

Managing asthma during pregnancy means keeping a close eye on both your lung function and your baby’s movements. Your healthcare team will guide you through this process.

Monitoring Lung Function

Your doctor may use one of two tools to check how well your lungs are working:

• Spirometry — a test that measures the volume of air you can breathe in and out
• Peak flow meter — a small handheld device you can use at home to measure how fast you can breathe out

Regular lung function checks help your doctor adjust your treatment if your asthma changes during pregnancy.

Monitoring Your Baby’s Movements

After 28 weeks of pregnancy, you should track your baby’s movements every day. A decrease in movement can be a warning sign. After 32 weeks, your doctor may use ultrasound to check your baby’s growth — especially if your asthma is not well controlled, or if you have moderate to severe symptoms.

If your baby’s movements decrease during an asthma episode, contact your healthcare provider right away or call 911 if the situation feels urgent.

Avoiding Asthma Triggers During Pregnancy

One of the best ways to reduce your need for medication is to avoid the things that trigger your asthma. Common triggers include:

• Cigarette smoke — avoid all smoke, including second-hand smoke
• Dust and dust mites
• Pet dander
• Mould
• Strong scents or chemical fumes
• Gastroesophageal reflux disease (GERD) — acid reflux is very common in pregnancy and can trigger asthma episodes; speak to your doctor about safe treatment options
• Nasal congestion and rhinitis — many pregnant women experience nasal symptoms, and these can make asthma worse

Therefore, keeping your home environment clean and smoke-free is one of the most effective steps you can take. According to the Mayo Clinic’s guide to asthma management, identifying and reducing exposure to your personal triggers can significantly improve asthma control.

Working With Your Healthcare Team

If more than one doctor is involved in your care — for example, a family doctor, an obstetrician, and a respirologist or allergist — it is important that they all communicate with each other. Your obstetrician should always be involved in decisions about your asthma treatment during pregnancy.

In Canada, you can ask your family doctor for a referral to a respirologist or an allergist if your asthma is difficult to control. Most provincial health plans cover these specialist visits. If you do not have a family doctor, a walk-in clinic can help you get started and refer you onward if needed.

For more information on asthma management, the World Health Organization’s asthma fact sheet provides a helpful global overview of the condition.

When to See a Doctor

You should speak to your family doctor or visit a walk-in clinic if:

• You are pregnant and have been diagnosed with asthma
• You develop new symptoms like wheezing or unusual shortness of breath during pregnancy
• Your current asthma medication does not seem to be working
• You are unsure whether your medications are safe to continue during pregnancy
• You want to get your flu shot

Call 911 or go to your nearest emergency room right away if you have a severe asthma attack that does not respond to your rescue inhaler, or if you notice a sudden decrease in your baby’s movements during an asthma episode.

Always talk to your doctor, obstetrician, or a qualified healthcare provider before making any changes to your asthma treatment during pregnancy.

Key Takeaways

• Asthma during pregnancy is common and manageable with the right care.
• Uncontrolled asthma carries more risk for your baby than properly used asthma medication.
• Most asthma medications are safe to continue during pregnancy — never stop treatment without speaking to your doctor first.
• Your healthcare team should monitor both your lung function and your baby’s growth throughout your pregnancy.
• Track your baby’s movements daily after 28 weeks and report any decrease to your doctor immediately.
• Avoid asthma triggers such as smoke, dust, and allergens to reduce your need for medication.
• Get the flu shot every year — it is safe, effective, and covered by most provincial health plans.
• If you have concerns, speak to your family doctor, visit a walk-in clinic, or ask for a referral to a specialist through your provincial health plan.