Pregnancy & Asthma

The importance of controlling asthma during pregnancy should not be underestimated. The hormonal and physical changes during pregnancy influence breathing patterns, which in turn, may have a direct effect on the health of both mother and baby. Oftentimes, pregnant women with asthma enjoy an uneventful pregnancy. However, a pregnant woman with severe asthma symptoms can experience breathing difficulties that may influence the outcome of her pregnancy. Every woman wants a healthy full-term pregnancy and monitoring asthma should be part of her healthy prenatal program.

Below, Dr. Michael Schatz, Vice-President of the American Academy of Allergy, Asthma and Immunology, addresses the risks of uncontrolled asthma and the importance of treating asthma during pregnancy.

How does pregnancy influence asthma?
Not only may asthma affect pregnancy, but pregnancy appears to affect the course of asthma as well. The data in the literature would suggest that in about a third of women their asthma worsens, about a third of the women improve and about a third of the women stay the same. The bottom line really is for a woman to realize that her asthma can change during pregnancy; therefore, it needs to be followed particularly closely so that any change is matched with an appropriate change of therapy.

Who is at risk for asthma-influenced complications during pregnancy?
Although patients with even mild asthma can sometimes have extra problems, it certainly appears that the more severe the asthma, the more likely the risks. Maternal death would be much more common in a person with more severe asthma.

Why is it important to control asthma symptoms during pregnancy?
It's certainly important that asthma be controlled during pregnancy for a number of reasons. Certainly the mother's discomfort is not the least among them. Not only is it important for the mother to feel good, but if you talk to any perinatologist, they will tell you that the best way to have a healthy baby is to have a healthy mother. And that includes things like sleeping through the night and certainly getting enough oxygen. So it's important for the mother's comfort and safety. It does seem to translate to the safety of the baby as well, so that complications such as poor growth of the unborn baby, premature delivery or even death of the baby appear to be much less likely to happen if the asthma's controlled.

What are some of the risks to the mother of uncontrolled asthma?
The most commonly reported one is preeclampsia, which is a blood pressure problem that can be very serious during pregnancy. Other ones have been reported as well, including vaginal bleeding, excessive vomiting during pregnancy, pre-term labor and, unfortunately, the very severe outcome is actually maternal death during pregnancy.

How often do these complications happen?
The usual incidence, for example of preclampsia, is about 7%. It appears that asthmatic patients may have about a doubling of that risk- it may occur in 14% of the asthmatic population. I think it is important to remember that for most of these risks, the problem appears to be less when the asthma is well controlled.

How does uncontrolled asthma affect the fetus?
Not only can asthma have an adverse effect on the pregnancy in the mother, but uncontrolled asthma can be a problem for the baby as well. Probably the most common one reported is lower birth weight- less growth of the baby before it is born. In addition, severe uncontrolled asthma has been associated with death of the baby and babies can be born prematurely. All of those things can occur when the asthma is particularly more severe.

Are these risks to the fetus common?
Fetal deaths appear in up to 1% of all births. For pregnant women with asthma it would appear that there's about a 30%-50% increased chance. So the risk in a patient with fairly severe asthma would be somewhere around 1.3% to 1.5% compared to the baseline risk of 1% in the general population.

Do these risks decrease if asthma is controlled during pregnancy?
Even severe asthma, if it's well controlled, probably doesn't increase most of these risks, particularly the risks for the baby. So there's just no question that control of asthma makes a difference.

Is it safe to take asthma medications during pregnancy?
One of the most important aspects of dealing with asthma during pregnancy is to try to make sure that the benefits of what we do outweigh the risks. And this important issue of balancing benefits and risks certainly comes up in terms of making decisions during pregnancy.

One of the difficulties is that we don't really know as much about the risks of medicines as we would like. But most of the information that does exist suggests that virtually all of the commonly used asthma medicines -at least the ones that have been around for a while-are not associated with inordinate risk. And if we balance that against the fairly definite risk of uncontrolled asthma-either to the mother or the baby or both-it definitely appears the risk of uncontrolled asthma is greater than the risk of the asthma medications.

How do you know if your asthma is well controlled?
Surprisingly, that hasn't necessarily been as well defined. But what women need to understand is that they should not have symptoms more than once or twice a week; it's not bothering their sleep at night any more than once or twice a month; and they're not needing a rescue inhaler every day. And ideally, they're not having episodes that take them to the emergency room. Along with breathing tests that help confirm that the person's lungs are working as well as possible, all of those are the type of control goals that one would have and they are particularly important during pregnancy.

What advice would you give to pregnant women with asthma?
I would certainly recommend working with an asthma specialist, along with the obstetrician, because I think asthma specialists working with the patient have the best chance of making sure that the asthma is going to be as well controlled as possible with the safest type of therapy. In addition, another very important aspect of managing asthma during pregnancy, is for the woman herself to be educated about her asthma; what she's taking and why, and to be able to communicate to her physician when things aren't going well.