Asthma and Pregnancy

Asthma is the most common condition affecting the lungs during pregnancy. Asthma affects approximately 8 percent of women in their childbearing years. Well-controlled asthma is not associated with significant risk to mother or baby but uncontrolled asthma can cause serious complications. With appropriate asthma treatment and control, most women with asthma in pregnancy can have a normal pregnancy and deliver a healthy baby. Overall, the risk of poorly controlled asthma is much greater than the risk of taking medications to control asthma.           

What is asthma and what are its symptoms?

Asthma is a condition characterized by obstruction in the airways of the lungs caused by

• Spasm of surrounding muscles.
• Accumulation of mucus.
• Swelling of the airway walls due to the gathering of inflammatory cells.

Asthmatic patients usually have a condition that can be reversed with vigorous treatment.

Individuals with asthma often describe what they feel in their airways as “chest tightness.” They also describe wheezing, shortness of breath and cough.

Symptoms of asthma can be triggered by allergens such as pollen, mold, animals, feathers, house dust mites and cockroaches, other environmental factors, exercise, infections and stress.

What are the effects of pregnancy on asthma?

The severity of asthma during pregnancy varies from one pregnant woman to another. However, it is difficult to predict the course that asthma will follow in a pregnant woman. During pregnancy, asthma worsens in about one-third of women, improves in one-third, and remains stable in one-third.

Although studies vary widely on the overall effect of pregnancy on asthma, several reviews find the following similar trends

• Women with severe asthma are more likely to worsen, while those with mild asthma are more likely to improve or remain unchanged.

• The change in the course of asthma in an individual woman during pregnancy tends to be similar on successive pregnancies.

The changes in asthma noted during pregnancy usually return to pre-pregnancy status within three months of delivery.

Effects of asthma on pregnancy and baby

Uncontrolled asthma can lead to maternal and foetal hypoxaemia which leads to complications during pregnancy and poorer birth outcomes.

For the mother, uncontrolled asthma can cause serious complications including

• High blood pressure in pregnancy
• Premature delivery
• Maternal death

For the baby, complications of uncontrolled asthma include increased risk of

• Stillbirth
• Fetal growth retardation
• Premature birth
• Low birth weight

In contrast, if asthma is well-controlled throughout pregnancy there is little or no increased risk of adverse maternal or fetal complications.

Treatment

The management of asthma during pregnancy is similar to that at any other time: treatment should be aggressive, with the aim of eliminating symptoms and restoring and maintaining normal lung function. Cooperation between the physician and obstetrician is important throughout pregnancy for women with severe asthma.

Asthma therapy during pregnancy is most successful if a pregnant woman receives regular medical care and follows her treatment plan closely.

Before becoming pregnant, women with asthma should discuss their condition with the healthcare providers to ensure their asthma is well-controlled before they are pregnant. Women who discover that they are pregnant should continue their asthma medications until they get further advice from their healthcare providers. Suddenly stopping asthma medications could be harmful to the mother and the baby.

The use of medications should not replace avoidance of allergens or irritants, as avoidance will potentially reduce medication needs. In general, asthma medications used in pregnancy are chosen based on the following criteria:

• Inhaled medications are generally preferred because they have a more localized-effect to the lung with only small amounts entering the bloodstream.
• In general, the same medications used during pregnancy are appropriate during labor and delivery and when nursing.

Bronchodilator medication

Short-acting inhaled beta2-agonists, often called “asthma relievers” or “rescue medications” are used as necessary to control acute symptoms.

Inhaled corticosteroids

Inhaled corticosteroids are preventive, or “asthma controllers”. This is the mainstay of treatment in persistent asthma and appears to have a good safety profile in pregnancy.

Combination of beta-2 agonist and corticosteroid

In this form of treatment, both medications are present in a single inhaler. This treatment should be given to those whose asthma is not well-controlled by the above medications.

Oral corticosteroids

These are sometimes necessary for severe asthma in pregnancy but usually only for short periods in patients with severe asthma exacerbations or throughout pregnancy in women with severe asthma. However, they are the most effective drugs for the treatment of patients with more severe asthma.

Corticosteroid nasal spray

A corticosteroid nasal spray should be considered in any patient whose allergic nasal symptoms are more than mild. These medications prevent symptoms and lessen the need for oral medications.

Influenza vaccine

Influenza vaccine is recommended for all patients with moderate and severe asthma. There is no evidence of associated risk to the mother or fetus.

Asthma education and prevention

Asthma education teaches strategies to recognize the signs and symptoms of asthma, avoid factors that trigger attacks and use asthma-controlling drugs correctly. Good control of asthma during pregnancy further reduces the risk of complications to both mother and baby.

Avoiding triggers

Several simple steps can help to control environmental factors that worsen asthma and trigger attacks. These include

• Avoid exposure to specific allergens that are known to cause the asthma symptoms, especially pet dander such as fur or feathers, house dust, non-specific irritants such as tobacco smoke, strong perfume and pollutants.
• Cover mattresses and pillows with special casings to reduce exposure to dust mites.
• Pregnant women should not smoke or allow smoking in their home.

In summary

It is important to remember that the risks of asthma medications are lower than the risks of uncontrolled asthma, which can be harmful to both mother and baby. The level of asthma control and the use of asthma medication need to be discussed with the doctor, ideally before pregnancy. The doctor should be notified whenever the mothers know that they are pregnant. Regular follow-up for evaluation of asthma symptoms and medications is necessary throughout the pregnancy to maximize asthma control and to minimize the complications of uncontrolled asthma.

Last Reviewed	:	19 October 2016
Writer	:	Dr. Ho Bee Kiau
Accreditor	:	Dr. Norhaya bt. Mohd Razali