Medically reviewed by
Richard C. Herring, MD
Increasing evidence indicates that uncontrolled asthma is a possible threat to maternal and fetal survival and fetal growth. The goals of asthma therapy during pregnancy are the same as in non-pregnant patients – to prevent hospitalization, emergency room visits, work loss, and chronic disability. Managing asthma in both situations also is similar. Allergens and irritants should be avoided, including exposure to pets and to the harmful effects from cigarette smoke. Medications should be chosen as safe for both the mother and the fetus. many anti-asthmatic medications are considered safe during pregnancy, but the pregnant asthmatic should be monitored by a subspecialist so as to optimize asthma control using the safest medications.
1. What is the outcome of a pregnancy complicated by asthma?
Recent studies indicate that maternal asthma which is adequately controlled during pregnancy does not increase the risk of maternal or infant complications. The recent studies also indicate that there is a direct relationship between lower birthweight and less controlled asthma. If the mother requires cortisone (steroids) orally or by inhalation, the pregnancy and its outcome does not appear to be adversely affected as long as the asthma is controlled.
2. Why would uncontrolled asthma affect the fetus?
Uncontrolled asthma causes a decrease in the oxygen content in the mother’s blood. Since the fetus gets its oxygen from the mother’s blood, decreased oxygen in her blood may lead to decreased oxygen in the fetal blood. This can lead to impaired fetal growth and survival. The fetus requires a constant supply of oxygen for normal growth and development. In some cases, women with asthma have had increased rates of prematurity and smaller babies.
3. Are asthma medications harmful to the fetus?
Asthma medications do not appear to be associated with increased congenital malformations. Theoretically, however, some of the asthma medications may contribute to an increased risk to the fetus. Observations in hundreds of pregnancies in women with asthma have demonstrated that most anti-asthmatic medications are appropriate for use in pregnancy. The risks of uncontrolled asthma appear to be greater than the risks of necessary asthma medications. However, any oral medication should be avoided unless necessary for the control of symptoms. In general, aerosol and sprays are preferred therapy.
4. What effect does pregnancy have on asthma?
Pregnancy may effect the severity of asthma. Asthma, in one large study, has been shown to worsen in 35% of women, improve in 28% and remain the same in 33%.
5. During what part of pregnancy will asthma change?
Asthma has a tendency to worsen during pregnancy in the late second and early third trimesters, however women may experience less asthma during the last four weeks of pregnancy. The majority of women with controlled asthma experience little difficulty with asthma during labor and delivery. Troublesome asthma during labor and delivery is extremely rare in women whose asthma has been adequately controlled during pregnancy.
6. Why does asthma improve for some women during pregnancy?
The exact reason is unknown. Increased levels of cortisone in the body during pregnancy may be an important cause of why the improvement can occur.
7. Why does asthma worsen for some women during pregnancy?
Some women may have gastroesophageal reflux causing belching, heartburn, etc. This reflux, sinus infections and increased stress may aggravate asthma. Often, a viral respiratory infection causes an exacerbation of asthma.
8. Can I receive allergy shots during pregnancy?
Allergy shots do not have an adverse effect on pregnancy, so they can be continued. However, they shouldn’t be started during pregnancy, and the dose should be carefully monitored because of the risk of an allergic (anaphylactic) reaction to the allergy shots. Such a reaction, though rare, could be harmful to the fetus.
9. Can Lamaze be used by asthmatics?
Yes, most women can perform the Lamaze breathing techniques without difficulty.
10. Can I breast-feed if I have asthma?
Breast feeding should not be discouraged. The transfer of drugs into breast milk has not been evaluated precisely, but there appears to be no evidence that anti-asthmatic drugs (theophylline, beta agonists, cromolyn sodium, steroids) and have fever drugs (antihistamines and decongestants) will adversely affect the nursing infant.
Controlled asthma during pregnancy appears to be essential to the good health of the mother and fetus. Pregnant women should be monitored regularly so that worsening of asthma can be countered by an appropriate change in the management program. When episodes of severe asthma are avoided, nearly all women with asthma have normal pregnancies.
