Asthma In Pregnancy: Symptoms, Causes, Effects And Treatment

Asthma in pregnancy occurs in about 4-8% of women (1). It is a condition where the airways develop chronic inflammation, making it harder to breathe because of spasms of the airways, which usually swell and narrow down during an asthma attack, causing severe breathing problems. Asthma during pregnancy may decrease the oxygen levels in maternal blood, affecting the amount of oxygen supplied to the fetus.

Poorly managed asthma in pregnancy may increase the risk of several complications. Read this post to know the symptoms, risk factors, complications, and management of asthma during pregnancy.

Read about the symptoms, causes, risk factors, complications, diagnosis, treatment, and prevention of asthma during pregnancy.

What Are The Signs And Symptoms Of Asthma?

Common signs and symptoms of asthma may include (2):

• Wheezing, a squeaky, whistling sound while breathing
• Coughing
• Breathing difficulties such as shortness of breath
• Chest tightness
• Rapid breathing

Cyanosis (bluish color) around lips and chest pain can also be felt during severe asthma attacks. It is recommended to consult asthma or allergy specialist for diagnosis. You may take medications during asthma attacks as prescribed by the doctor.

Can Asthma Symptoms Change During Pregnancy?

Approximately one-third of pregnant women experience worsening asthma symptoms, and some may experience improvement of symptoms or no changes at all. However, any changes in asthma symptoms during pregnancy are temporary and return to pre-pregnancy condition within three months after childbirth (3).

Although it is difficult to predict how asthma will change during pregnancy, most women who had increased or decreased asthma symptoms in one pregnancy experience similar changes later.

What Are The Causes Of Asthma?

The exact cause of asthma is not known. However, genetic and environmental factors may play a role in developing asthma. The following factors may trigger or be linked with asthma (4):

• Genetic factors: Asthma runs in families. Affected parents can have children with the same condition.

• Respiratory infections: Lung tissue can be damaged from respiratory infections in infancy and early childhood. These damages may impact lung functioning and trigger asthma from a young age.

• Allergies: Certain allergies are linked to asthma and can trigger asthma symptoms. Allergies can also run in families.

• Environmental factors: Exposure to irritants, allergens, and certain viral infections during early childhood can cause asthma. The immature immune system and lung tissue damage from inflammation may play a role in asthma development. Constant exposure to dust or other hazardous irritants can also trigger adult-onset asthma.

According to the American College of Allergy, Asthma and Immunology (ACAAI), pregnancy does not increase the risk of developing asthma. However, some women with mild asthma may notice their symptoms during pregnancy.

How Does Asthma Affect Pregnancy?

Complications are rare if maternal asthma is well controlled with medication during pregnancy. Asthma decreases oxygen levels in the maternal blood, and the fetus gets oxygen from the mother’s blood. The oxygen supply to the fetus can be compromised in uncontrolled maternal asthma. A constant supply of oxygen is needed for optimal growth and development of the fetus (5).

The following asthma complications are rare but possible during pregnancy (5) if the attacks are not well-prevented and under control:

• Increased risk for premature birth
• High blood pressure and increased risk for preeclampsia (6)
• Low infant birth weight
• Impaired fetal growth
• Fetal malformations (cardiac, lip, and palate clefts)

Although these complications are seen in many pregnant women with asthma, it is unknown whether asthma is the direct cause. Asthma during pregnancy is not related to congenital malformations and spontaneous abortion (miscarriage). Keeping asthma under control throughout pregnancy may reduce the risk of these complications (5).

How Is Asthma Diagnosed?

Medical history, symptoms, and physical examination may help identify some asthma signs. Diagnosis of asthma is essentially made on clinical signs, which are not modified by pregnancy. Chest X-ray and lung function tests can be prescribed to confirm the diagnosis. In addition, doctors may ask or give questionnaires to understand triggering factors such as allergies and exposure to irritants (7).

Lung function tests (pulmonary function tests) can determine lung functioning. These tests are done before and after using a bronchodilator. Lung function improves in people with asthma when the bronchodilators open the airways.

Lung function is assessed using the following tests (7):

• Spirometry measures the amount of air you inhale and exhale.

• Peak airflow meters measure the ability to push air out of the lungs (expel air).

• FeNO tests measure exhaled nitric oxide, which helps understand the degree of inflammation in the lungs.

• Provocation tests help determine the lungs sensitivity, and are also called challenge or trigger tests. Methacholine, irritant, and exercise challenges are common provocation tests for asthma.

Sometimes doctors may order other tests, such as sinus X-rays, acid reflux tests, and allergy tests to rule out or identify asthma triggers. Improvement of symptoms with asthma medications also confirms the diagnosis.

How Is Asthma Treated During Pregnancy?

Most asthma medications are safe in pregnancy. If you are already diagnosed with asthma, you may visit the allergists or primary care provider before planning pregnancy. They can ensure that the asthma is well controlled and the current medications are safe during pregnancy. If you are already pregnant, do not delay consultation.

The following medicines are prescribed to manage asthma symptoms during pregnancy (5):

• Short-acting inhaled bronchodilators such as albuterol or other b2 mimetics
• Inhaled corticosteroids such as budesonide
• Leukotriene inhibitors such as montelukast (Singulair)

Long-acting beta-agonists such as Symbicort, Serevent, and Advair are not considered for first-line asthma treatments in pregnant women. These medications have only been opted if the above medications fail to control asthma.

The risk of stopping asthma medication in pregnancy is greater than any medications since moderate to severe asthma attacks can affect the mother and baby. Allergists may plan the asthma regime for each woman based on risks and benefits.

What To Do If Asthma Worsens During Pregnancy?

Asthma exacerbations are common in pregnancy. Usually, women who have visited their doctors before or during early pregnancies are instructed about the action plans. If not, you may contact the health care provider to know individualized asthma action plans (5).

Never hesitate to seek emergency medical care if you are concerned or have severe symptoms. Oral corticosteroids such as prednisone are prescribed for severe asthma during pregnancy with no severe harm to the baby.

How To Avoid Asthma Attacks During Pregnancy?

The following ways may help prevent asthma attacks during pregnancy (5):

• Keep asthma well-controlled with medications.

• Avoid asthma triggers, i.e., exposure to allergens, such as pollen, cockroaches, molds, pet dander, and dust mites.

• Avoid contracting respiratory infections by using a mask or keeping yourself away from infected persons.

• Avoid cigarettes or any forms of tobacco smoking and secondhand exposure to smoke. Smoking can also harm the baby.

• Practice regular exercise and take quick-relief medications as prescribed before exercises to tolerate the excursion.

• Visit the doctor and update the asthma action plan for pregnancy before planning a pregnancy.

• Always use approved asthma medications with prescriptions to help control asthma.

What To Do If You Get An Asthma Attack During Labor?

You can safely use the reliever inhaler to control asthma symptoms during labor. However, an asthma attack rarely occurs during labor and childbirth. During prenatal visits, you may also inform your obstetrician or midwife about allergies and asthma. This may help them prepare for labor and delivery accordingly (8).

What Are The Different Types Of Asthma?

Asthma can be classified based on severity, onset, response to treatment, and causes (9) (10).

Based on the severity and frequency of symptoms, asthma is classified into four types :

• Mild intermittent asthma symptoms do not interfere with daily activities, and the mild symptoms often last less than two nights in a month or two days per week.

• Mild persistent asthma is when symptoms occur more than two times a week and up to four nights in a month.

• Moderate persistent asthma occurs when symptoms are seen daily and one night a week, and some daily activities are limited.

• Severe persistent asthma symptoms occur most nights and several times a day. This may limit regular activities.

Based on the response to treatments:

• Well-controlled asthma is when the symptoms are less than two days a week, and there are no night symptoms. The need for reliever medications is also limited to less than two times a week, no flare-ups or asthma attacks, and does not affect daily activities.

• Poorly controlled asthma is experiencing asthma symptoms during daily activities and night and needs reliever medications regularly.

Based on the onset of asthma:

• Acute asthma refers to asthma attacks or flare-ups when the symptoms are severe.

• Adult-onset asthma is when the diagnosis of asthma is first made in adulthood.

Based on the causes:

• Allergic asthma is when asthma symptoms are triggered or caused by allergens.

• Non-allergic asthma is not related to any allergic causes. The exact causes are unknown.

Other types of asthma may include:

• Chronic asthma is present for the long term., and can often cause asthma-COPD overlap, and the treatments may vary.

• Exercise-induced bronchospasms (exercise-induced asthma) are temporary narrowing of the airways during vigorous exercise.

• Occupational asthma is a new onset of asthma developed due to workplace triggers such as chemicals or fumes.

• Work-exacerbated asthma is when asthma worsens due to workplace triggers.

• Bronchial asthma is narrowing and swelling of the airways, causing wheezing.

• Nocturnal asthma is worsening asthma symptoms at night.

• Seasonal asthma is an asthma flare-up due to seasonal triggers such as cold in winter or pollen in spring.

• Viral asthma is primarily triggered by viral upper respiratory infections such as flu or cold.

• Reactive airways are an overreaction of the bronchial tube to irritants. It refers to a person with asthma symptoms but has not been diagnosed with asthma.

• Thunderstorm asthma(2016 epidemic) is triggered by a combination of high grass pollen and a certain type of thunderstorm.

• Severe asthma or brittle asthma is when continuous high-dose medications are needed to control the asthma symptoms.

• Difficult to treat asthma is a type that remains unchanged despite high-dose medications.

• Refractory asthma or treatment-resistant asthma is stubborn or unmanageable asthma. However, monoclonal antibody therapies may improve this asthma.

• Silent asthma is often used if a person with asthma does not tend to wheeze. However, it is not necessary to hear wheezing to diagnose asthma.

Asthma is a rare reason to avoid pregnancy. However, it is important to treat asthma during pregnancy to avoid complications for the mother and the baby. Never stop taking asthma medications during pregnancy since it does more harm than good. You should also avoid asthma triggers during pregnancy.

References

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