Asthma And Pregnancy: Symptoms, Risks, Prevention, And Treatment

What is asthma?

Asthma is a chronic, inflammatory disease that affects your airways and breathing by inflaming and narrowing the passages (bronchial tubes) that bring oxygen to your lungs.¹

There is no cure for asthma yet, but research shows the following therapies can be effective treatments (sometimes in combination with each other):²

• Taking prescription medications like corticosteroids

• Avoiding allergens and triggers like pollen or cold, dry air

• Reducing or managing stress with mind-body techniques like meditation

Some studies indicate that roughly a third of pregnant women with asthma will have worse asthma during pregnancy.³

Another third will have an improvement in their symptoms.

The remaining third won’t experience any changes.

How common is asthma during pregnancy?

Asthma is one of the most common chronic diseases experienced during pregnancy.

A 2006 review found that rates of self-reported asthma for pregnant women in the US were between 8.4% and 8.8% of women surveyed, making it quite common.⁴

Can asthma begin during pregnancy?

According to the American College of Allergy, Asthma & Immunology, “there is no research that indicates you can develop asthma from being pregnant.”⁵

However, for those unaware of having asthma, pre-pregnancy symptoms that were once mild could suddenly become apparent (flared).

As such, you might seek and receive an asthma diagnosis for the first time due to pregnancy.

It is likely that your asthma was subclinical (not severe enough to be diagnosable) before you became pregnant.

Does asthma make pregnancy high-risk?

People with asthma generally experience pregnancy and childbirth without complications, especially when their asthma is well-managed.

However, having undiagnosed or aggravated asthma while pregnant can increase risks for both mother and child due to factors like decreased oxygen levels during an asthma attack.⁶ ⁵

A recently updated StatPearls article, Asthma in Pregnancy, indicates that asthma will complicate 4-8% of pregnancies.³

Symptoms of asthma during pregnancy

Asthma during pregnancy usually features typical asthma symptoms, such as:

• Wheezing

• A constant cough that worsens at night or in the early morning

• Shortness of breath

• A tight feeling in the chest

What intensifies asthma symptoms while pregnant?

If your asthma worsens during pregnancy, it may be due to:

Exposure to triggers

To manage your asthma optimally while pregnant, you must be cautious and avoid known triggers. It would benefit you to reduce your exposure to allergens, quit smoking (or keep your distance from smokers), and stay away from anyone with a respiratory infection.

Insufficient exercise

Some women stop or reduce their exercise levels during pregnancy. However, as long as you follow your doctor’s recommendations and guidelines for exercising, you can gain many health benefits - including reduced stress (acute stress can be an asthma trigger). 

Temporary changes that can aggravate asthma

A few changes in your body caused by pregnancy might impact your asthma severity, including:

• Your uterus is expanding and pressing on your diaphragm As the uterus grows during pregnancy, it pushes into the diaphragm, which is a muscle that pulls air into your lungs. This change results in slightly less space in your chest and lungs. The 26th and 34th weeks of pregnancy are when the uterus and fetus press on the diaphragm the most.⁷

• Resting breathing rate changes Aspects of your breathing will fluctuate during pregnancy, including the number of breaths you take per minute.⁷

• Changes in immunity How your body regulates your immune system while pregnant can cause changes that help your developing baby thrive. However, these shifts can also produce a type of protein (cytokines) known to trigger asthma.³

• Hormonal changes Hormonal shifts during pregnancy, such as rising estrogen levels, can increase mucus in the nose and sinuses, which can cause asthma aggravating post-nasal drip.⁸

In most individuals, asthma symptoms return to pre-pregnancy levels within three months of giving birth.³

Risk factors for asthma during pregnancy

The primary risk factor for asthma in pregnancy is pre-existing asthma. 

Smoking will also increase your risk of developing significant asthma symptoms while pregnant.⁹

Asthma diagnosis

If you do not yet have an asthma diagnosis and are experiencing symptoms, your doctor will need to examine you and your medical history. They will then likely order a lung function test (called spirometry) to help distinguish your symptoms from asthma or another health concern. The inflammation caused by asthma can make you prone to bronchitis or pneumonia, so doctors will usually seek to rule out a possible chest infection.

Spirometry as a diagnostic tool

If you have new asthma-like symptoms, doctors will usually order a test called spirometry.

Spirometry (pronounced “spy-rom-uh-tree”) is a common test that checks how your lungs are functioning. Spirometry is a simple test - it isn’t invasive or painful. During a healthy pregnancy, this test will not pose a risk to the fetus.¹⁰

The process involves having a clip placed on your nose to close your nostrils. You will be asked to breathe in and out into a special mouthpiece that measures the volume of air you inhale and exhale. It can show:¹¹

• The amount of air you can breathe in and out

• How fast/slow you can blow air out of your lungs

If you have already been diagnosed with asthma, your obstetrician may order spirometry testing to periodically evaluate how pregnancy is affecting your breathing.

How does unmanaged asthma affect pregnancy?

According to research, poorly-controlled asthma can present several risks during pregnancy, including (but not necessarily limited to):¹²

• Low birth weight

• Premature birth

• High blood pressure

• Neonatal hypoglycemia (newborn has low blood sugar)

• Congenital abnormalities

• Respiratory failure

If you have asthma, talk to your doctor as soon as you know you are pregnant so that they can monitor your condition and adjust your medications if needed.

Treating asthma while pregnant

Asthma treatment generally remains the same during pregnancy, as most asthma medications are safe to take while pregnant.

If your symptoms worsen, your doctor may increase your medication or prescribe another medication.

Or, if your symptoms improve during pregnancy, your physician may temporarily lower your medication dosage (to lower any risks to the developing fetus as much as possible).

However, take care to discuss your symptoms with your healthcare provider. 

Do not make spontaneous changes to the way you use your asthma medication(s) without consulting your doctor.

Inhaler medications

There are two main types of inhaled prescription medications used to treat asthma:

Relievers (short-acting bronchodilators)

Often known as rescue or reliever inhalers or colloquially “puffers,” these medications open your airways when you’re having difficulty breathing or experiencing an acute asthma attack.

Their effects can be rapid but also short-acting.

According to the Centers for Disease Control and Prevention (CDC), these puffers are generally safe during pregnancy when used as prescribed.¹³

However, relievers may pose a slight risk of increased congenital abnormalities. Still, researchers have yet to distinguish whether asthma, health issues related to having asthma, or asthma medication are responsible.¹³

One way to minimize the use of this class of medications is to avoid your triggers as much as possible while pregnant.

Preventers (anti-inflammatory corticosteroids)

Low-dose preventer inhalers are used in asthma maintenance or to prevent flare-ups. They are not used when you are having an acute asthma attack. These preventer puffers contain corticosteroid medications that help lower the inflammation in your lungs, thereby improving your asthma over a longer period.

A preventer inhaler is typically used twice daily. 

If your asthma symptoms worsen, your doctor may suggest using your inhaler more often, increasing the amount of medication it delivers, or switching you to another type of preventer medication that is also safe to use in pregnancy.

Control medications

Oral corticosteroids

Inhaled corticosteroids are usually the go-to treatment for persistent asthma symptoms during pregnancy, but in the case of severe asthma attacks, oral corticosteroids may be necessary.¹⁴

Anti-leukotriene agents

Doctors sometimes prescribe this class of asthma drugs to those who don't tolerate corticosteroids well, but their use in pregnant women is understudied.

The benefits of keeping asthma in check with medication generally outweigh the risks, so doctors tend to keep patients on the same medication unless there is a clear indication to do otherwise. 

Asthma monitoring and prevention

At-home spirometry

It is possible to check your lung function with an at-home digital spirometry test connected to a smartphone.

Peak flow meter

There is a cheaper and more widely available tool called a peak flow meter that measures how much air you can breathe out and shows how well your lungs are working. It is an easy tool with a mouthpiece that you blow into. You use it at home, and it is completely painless and safe for you and your unborn baby to use daily. However, unlike digital spirometry, you will have to write down your own results to show your doctor.

Prevent acid reflux by eating smaller meals

Acid reflux disease is common during pregnancy and can worsen your asthma symptoms. Your doctor may recommend eating smaller, more frequent meals to reduce the risk.

Sleep elevated

If possible, elevate your upper body slightly while sleeping. Use pillows to raise your shoulders and neck. This helps make it easier to breathe and reduces the risk of breathlessness.

Labor and delivery

Practice diaphragmatic breathing (belly breathing) before your due date, as this will assist with managing pain and maximize your oxygen intake.

It is extremely rare for an asthma attack to occur during labor and delivery, but if it does, medication can help.⁵

You are unlikely to have asthma-related breathing difficulties during labor and delivery with well-controlled asthma.

Your care team may want to make specific arrangements before labor and delivery.

For example, suppose you need an emergency cesarean section (C-section). In that case, your anesthetist will use medications that promote the opening of the airways, so it is important that your anesthetist also knows you have asthma.

The lowdown

Asthma is the most common respiratory complication experienced during pregnancy. Your asthma symptoms may stay the same, worsen, or even improve while pregnant. Managing asthma effectively when pregnant is about avoiding flare-ups, maintaining your overall health, and optimizing your baby’s growth. It is considered safer for pregnant women with asthma to be treated with medications than to suffer an asthma attack. 

If you have asthma, consult with your doctor as soon as you find out you are pregnant. Your obstetrician can help develop a care plan to facilitate the best possible health outcomes for you and your baby.