Pregnancy and Asthma - Information for Health Care Providers

Asthma is one of the most common illnesses that complicate pregnancy.

Asthma may occur for the first time during pregnancy, or it may change during pregnancy; in about one-third of pregnant women asthma symptoms will worsen during pregnancy, one-third will remain the same, and one-third will improve. Exacerbations are common in pregnancy, particularly in the second trimester. In any case, pregnant women with asthma need treatment to control their asthma and thus protect their health and the health of their fetus. (1)
Pregnant women and women planning a pregnancy should be asked whether they have asthma so that appropriate advice about asthma management and medications can be given. If objective confirmation of the diagnosis is needed, it would not be advisable to carry out a bronchial provocation test or to step down controller treatment until after delivery. (1)

Uncontrolled asthma during pregnancy can produce serious maternal and fetal complications such as pre-term delivery, low birth weight, increased perinatal mortality. When asthma is properly controlled, however, pregnant women with asthma can maintain a normal pregnancy with little or no increased risk to themselves or their fetuses.

Although there is a general concern about any medication use in pregnancy, the advantages of actively treating asthma in pregnancy markedly outweigh any potential risks of usual controller and reliever medication; even when their safety in pregnancy has not been unequivocally proven. (1)
The goals of therapy for pregnant women with asthma is to provide optimal therapy to maintain control of asthma for maternal health and quality of life as well as for normal fetal maturation. (2) Learn more about asthma control.
The obstetrical care provider should be involved in asthma care, including monitoring of asthma status during prenatal visits. A team approach is helpful if more than one clinician is managing the asthma and the pregnancy. (2) Learn when to refer patients to an asthma specialist.

There are four integral components of effective asthma management (2)

1. Assessment and monitoring of asthma, including objective measures of pulmonary function.
Maternal lung function:

Pregnant women should receive frequent monitoring because the course of asthma changes for approximately two-thirds of women during pregnancy. Women who have persistent asthma should be evaluated at least monthly during pregnancy by means of history (symptom frequency, nocturnal asthma, interference with activities, exacerbations, and medication use), lung auscultation, and pulmonary function.
Spirometry tests are recommended at the time of initial assessment. For routine monitoring at most subsequent follow-up outpatient visits, spirometry is preferable, but measurement of peak expiratory flow (PEF) with a peak flow meter is generally sufficient.
Patients should be instructed to be attentive to fetal activity. Serial ultrasound examinations starting at 32 weeks gestation may be considered for patients who have suboptimally controlled asthma and for women with moderate to severe persistent asthma. Ultrasound examinations are also helpful after recovery from a severe exacerbation.

2. Avoid or control asthma triggers.
The identification and control of triggers–factors that induce airway inflammation or precipitate asthma exacerbations–are important in controlling asthma during pregnancy. Common triggers include dust, pet dander, and cigarette smoke. Although immunotherapy should not be started during pregnancy, ongoing immunotherapy may be continued to reduce the response to a specifically identified allergen.

If the patient is a smoker, it is important to encourage quitting, for the health of the baby and the mother. If the patient is exposed to second-hand smoke regularly, strategies to avoid the smoke, and helpful information about quitting smoking should be given. Maternal smoking may be associated with increased risk for wheezing and development of asthma in her child.
3. Establish medication plans for chronic management of asthma and for managing exacerbations using preferred medications.

It is safer for pregnant women with asthma to be treated with asthma medications than to have asthma symptoms or exacerbations and reduced lung function that may potentially impair oxygenation for the fetus. The type and amount of medication necessary to meet the goals of therapy are dictated by the severity of the patient’s asthma.
The stepwise approach to therapy, in which the dose and number of medications and frequency of administration are increased as necessary and decreased when possible, is used to achieve and maintain asthma control. Before stepping up medications, assess the patient’s technique in using the medications correctly and check fill and pick-up history.
Gaining control of asthma: The clinician judges individual patient needs and circumstances to determine at what treatment step to initiate therapy, while focusing on the health and well-being of both the mother and the fetus. Assessment of the patient’s asthma history, current symptoms, and objective measures are all important in making this determination. For example, pregnant women with asthma may have minimal symptoms but still have abnormal pulmonary function tests and potentially impaired oxygenation.
Maintaining control of asthma: Once control is achieved and sustained for several months, a step down to less intensive therapy may be considered for pregnant patients (2); however, given the evidence in pregnancy and infancy for adverse outcomes from exacerbations during pregnancy, including due to lack of ICS or poor adherence, and evidence for safety of usual doses of ICS and LABA, a low priority should be placed on stepping down treatment (however guided) until after delivery, and ICS should not be stopped in preparation for pregnancy or during pregnancy. (1)

Medications:

Albuterol is the preferred short-acting, short-duration beta2-agonist for use during pregnancy. This drug is very selective for the beta2-receptor and possesses an excellent safety profile for both pregnant and nonpregnant women with asthma. (2)
Use of inhaled corticosteroids (ICS), beta2-agonists, montelukast or theophylline is not associated with an increased incidence of fetal abnormalities. ICS reduce the risk of exacerbations of asthma during pregnancy and cessation of ICS during pregnancy is a significant risk factor for exacerbations. (1)
During labor and delivery, usual controller medications should be taken, with reliever if needed. (1) Asthma is often inactive during labor and delivery, but consideration should be given to assessing PEF rates on admission and at intervals during labor. (2)

Medication risk:

Human gestational studies were identified for the inhaled corticosteroids (ICSs) beclomethasone, budesonide, and triamcinolone and for cromolyn sodium, theophylline, and salmeterol. Human pregnancy data support an FDA Pregnancy Category B rating for budesonide. Pregnancy Category B ratings for cromolyn, nedocromil, montelukast, and zafirlukast are based primarily on safety in animal reproduction studies. ICSs other than budesonide, theophylline, zileuton, and long-acting β2-adrenergic agonists are Pregnancy Category C. (3)
Data from the National Birth Defects Prevention Study (NBDPS) was used to examine maternal asthma medication use during pregnancy and the risk of certain birth defects. Asthma medication use during pregnancy did not increase the risk for most of the birth defects studied, and might increase the risk for some birth defects, such as esophageal atresia, anorectal atresia, and omphalocele. However, it was difficult to determine if asthma or other health problems related to having asthma increased the risk for these birth defects, or if the increased risk was from the medication use during pregnancy. (4)

Pregnant patients should not delay seeking medical help in the emergency department or hospital if any of the following occur:

therapy does not provide rapid improvement
improvement is not sustained
there is further deterioration
the asthma exacerbation is severe
the fetal kick count decreases

4. Educate pregnant patients to develop a partnership in asthma management. (2)
It is recommended that the clinical team members help to ensure that the pregnant woman has access to education about asthma so that she can understand the potential interrelationships between asthma and pregnancy, and what she can do to have a healthier pregnancy.

It is of the greatest importance for pregnant women with asthma to understand that they are “breathing for two.”
These women need information on how to properly control and manage their asthma during pregnancy to reduce the risk to the fetus.
Concerns of pregnant women need to be elicited and addressed.

References

1. Global Initiative for Asthma (GINA) 2020 Guidelines (pdf)
2. NAEPP expert panel report. Managing asthma during pregnancy: recommendations for pharmacologic treatment-2004 update
3. Asthma controller therapy during pregnancy
4. CDC: Maternal Asthma Medication Use and the Risk of Selected Birth Defects