With an estimated 300 million people affected worldwide, asthma is one of the most pervasive chronic conditions in existence1. It is the most common, potentially serious, medical condition that can complicate a pregnancy2.
Maternal asthma is associated with various adverse perinatal outcomes, and changes in the course of the disease often occur during pregnancy. Up to 45% of asthmatics report unpredictable exacerbation of symptoms requiring medical attention while pregnant4. It is therefore essential to carefully manage asthma during pregnancy to protect the health of both the mother and child.
Effects of Pregnancy on Maternal Asthma
Various trends have been found between pregnancy and asthma.
- Women with existing severe asthma are more likely to have a worsening of the condition while pregnant.
- Women with mild asthma are more likely to remain unchanged or have an improvement in the condition while pregnant.
- Exacerbations of asthma are most likely to occur during weeks 24 to 36 of gestation. Less than 10% of patients becoming symptomatic during labor and delivery.
- A change in the course of asthma during pregnancy tends to be repeated in future pregnancies.
- Women that experience changes in their asthma during pregnancy usually return to their pre-pregnancy status within three months of delivery.
Hormonal changes during pregnancy can also affect the lungs, sinuses, and nose.
- An increase in the estrogen adds to congestion of the capillaries in the lining of the nose, causing nasal congestion (stuffy nose) often experienced during the third trimester
- An increase in progesterone increases respiratory drive, which may result in a feeling of shortness of breath
Effects of Maternal Asthma on Mother and Fetus
Uncontrolled asthma can result in the exacerbation of asthma attacks, which characteristically involves wheezing, coughing, and shortness of breath, as well as chest pain and/or tightness3. For pregnant women, uncontrolled asthma reduces maternal blood oxygen content, upon which the fetus depends. The fetus requires a constant supply of oxygen for normal growth and development, so decreased oxygen levels can result in impaired fetal growth and survival.
According to the American College of Allergy, Asthma & Immunology2, uncontrolled maternal asthma has the potential to affect both the mother and the fetus.
Effects on the mother may include:
- Premature delivery
- Death (rarely)
Effects on the fetus may include:
- Fetal growth retardation
- Premature birth (especially with oral steroid use)6.
- Low birth weight
- Low APGAR score
- Increased risk of stillbirth
There is evidence to suggest that adequate control of asthma during pregnancy improves fetal growth, and reduces the chance of fetal or newborn death5.
Effective Management of Maternal Asthma
The goals of asthma management during pregnancy include the maintenance of optimal asthma control and prevent exacerbations4. However, the ultimate goal of managing asthma is to ensure that fetal oxygen levels remain adequate for normal growth and development3.
Because the effects of pregnancy on a woman’s asthma are variable, women with persistent asthma should have their lung function monitored throughout their pregnancy using spirometry. Additionally, ultrasounds should be performed during the first trimester to evaluate fetal growth restriction, and determine the risk of preterm birth. Beginning at 32 weeks gestation, ultrasound examinations to examine fetal activity and growth should be used in patients with uncontrolled asthma, in those that have moderate to severe asthma, and in those that are recovering from a severe asthmatic attack3.
Many pregnant women with asthma need to use medication to maintain their normal lung function. Long-acting medications, such as inhaled corticosteroids, are used to prevent the flare-ups of symptoms. On the other hand, short-acting medication, such as inhaled albuterol, provides immediate symptom relief. No matter what therapy is used in pregnancy, it should be tailored to the patient so that the lowest dose of medication is used to control their symptoms3.
Avoiding an Asthma Attack
In addition to effective medical management of asthma during pregnancy, avoiding potential asthma triggers is particularly important during pregnancy. Pregnant women who suffer from asthma should avoid allergens such as animal dander, pollen, dust mites, cockroaches, and mold5, and they should stay away from people who have respiratory infections.
If asthma is exacerbated by acid reflux, pregnant women should eat smaller, more frequent meals, avoid eating for a few hours before bed, elevate their head while in bed, and avoid foods that trigger acid reflux symptoms3.
Proper management of asthma during pregnancy reduces risk complications and improves both maternal and fetal outcomes.
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