Asthma is probably the most common, potentially serious medical problem that occurs during pregnancy. Some studies have suggested that asthma complicates up to seven percent of all pregnancies. However, with appropriate treatment and care, the prognosis for a successful pregnancy is outstanding.
When asthma exists in pregnant women, there may be a somewhat greater risk of delivering prematurely, or delivering an infant of low birth weight. High blood pressure problems — hypertension, or a related condition known as pre-eclampsia — have also been diagnosed more frequently in pregnant women with more severe asthma than in their more healthy counterparts. But physicians are as yet uncertain to what degree the uncontrolled asthma directly provokes these problems, or whether other circumstances are more involved. However, current information suggests that optimal control of asthma during pregnancy is the best way to minimize the risk of complications.
Uncontrolled Asthma and the Fetus
Uncontrolled asthma causes a decrease in the oxygen content of the mother's blood. Since the fetus gets its oxygen from the mother's blood, this condition leads to decreased oxygen in the fetal blood. The result may be impaired fetal growth and survival since the fetus requires a constant supply of oxygen for normal growth and development. There is evidence that adequate control of asthma during pregnancy reduces the chances of death of the fetus or newborn infant and improves fetal growth inside the uterus.
There are no indications that asthma in the pregnant woman contributes to either spontaneous abortion or congenital malformation of the fetus.
Changes in Severity of Asthma During Pregnancy
Medical experts believe that about one-third of pregnant women with asthma will experience increased symptoms during the pregnancy; another third will remain the same; and yet another third will experience a lessening of symptoms. Most pregnant asthmatic women whose symptoms change in one way or another will return to their pre-pregnancy condition within three months after giving birth. There is a tendency, though, for women whose asthma symptoms increase or decrease during one pregnancy to experience the same pattern in subsequent pregnancies.
It is difficult to predict in an individual woman the direction or degree of change in her asthma symptoms during pregnancy. Because of this uncertainty, her asthma should be followed closely so that any change can be promptly matched with an appropriate change in therapy. This is a good reason for professional teamwork between the woman's obstetrician and an allergy specialist, the latter having particular knowledge and "tools" to manage and control the asthma.
Significant asthma symptoms—including asthma attacks —almost never occur during labor and delivery in women who have properly cared for their asthma during their pregnancies. Also, most asthmatic women are able to perform Lamaze breathing techniques during their labor without any difficulty.
Effective Self-Management During Pregnancy
Avoiding the conditions that trigger asthma is always important, but is particularly important during pregnancy. Patients should increase avoidance measures in order to gain maximum comfort with a minimum of medication. Giving up cigarette smoking is very important since maternal smoking may make the asthma worse and directly affects the health of the growing fetus as well. Also, minimizing contact with people who have respiratory infections — and avoiding allergens such as dust mites, animal dander, pollen and cockroach debris — are recommended during pregnancy.
Asthma Medications During Pregnancy
A number of asthma medications are considered "safe" for the pregnant patient because their risks appear to be less than the risks of uncontrolled asthma. These include inhaled bronchodilators, cromolyn sodium and beclomethasone, all of which have a local — not system-wide — effect. Theophylline is also considered appropriate during pregnancy if asthma is not adequately controlled by the above medications. Finally, oral steroid medications, such as prednisone, should be used when necessary for severe asthma during pregnancy.
If allergy shots are part of the ongoing therapy for the asthmatic woman who has become pregnant, they can usually be continued if no systemic reactions to the shots are being experienced. As an extra precaution, though, the dosage of the allergy extract being used may be reduced somewhat in order to decrease the chance that a severe allergic reaction might occur during the pregnancy.
Q. Should I do special exercises as a pregnant asthmatic woman?
A. Certainly regular exercise is important to health, and your obstetrician is your best advisor about exercising during your pregnancy. Swimming is known to be a particularly good exercise for people with asthma. Using an inhaled bronchodilator ten minutes before you exercise may help you better tolerate your recommended exercise during pregnancy.
Q. Should flu shots be taken during pregnancy?
A. Flu shots are generally recommended for asthmatic patients, and pregnancy does not alter that recommendation. In fact, some information has suggested that influenza may be particularly severe in pregnant women.
Q. Is it safe to breast-feed?
A. Although the transfer of most asthma medications into breast milk has not been precisely studied, physicians do not believe they have an adverse effect, in usual doses, on the nursing infant. When breast-feeding, drinking extra liquids to avoid dehydration is also important (as it is for all people with asthma).
SOURCE: This information should not substitute for seeking responsible, professional medical care. First created 1995; fully updated 1998; most recently updated 2005.
© Asthma and Allergy Foundation of America (AAFA) Editorial Board