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Practical Tips for Pregnant Women with Allergies & Asthma

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Asthma and other allergic problems are among the most common of potentially serious illnesses complicating pregnancy. Here are answers to some of the most common questions women ask about managing allergies & asthma during pregnancy.

Will asthma have any effect on my pregnancy and on the baby?
If uncontrolled, severe asthma may be harmful to the developing fetus. However, if well-controlled, it should not have an adverse effect on you or your baby.

How does severe, uncontrolled asthma adversely affect the fetus?
The developing fetus depends on the mother to supply oxygen for growth and survival. Oxygen dissolved in her blood is transferred through the placenta to the fetus. Uncontrolled asthma causes a decrease in the mother’s oxygen, which in turn, reduces the oxygen available to the developing fetus. This may result in impaired fetal growth; it could even affect the baby’s survival.

Will my asthma worsen during pregnancy? Is there any greater risk during labor and delivery?
Your asthma may worsen, stay unchanged, or possibly improve during pregnancy. Although it cannot be accurately predicted in a first pregnancy, asthma usually follows the same course in subsequent pregnancies. For reasons not totally understood, asthma usually improves during labor and delivery, but even if a severe attack occurs, appropriate treatment can be given and complications are rare.

Is there anything that I can do to prevent symptoms of asthma or allergies and lessen the need for medications?
Avoid asthma triggers, such as cigarette smoke, exposure to animals, and dusty and damp environments. Stay in an air-conditioned place during pollen seasons and when the pollution index is high. Avoid crowds where cold and flu viruses may be prevalent. Avoid foods or chemicals that might have caused a reaction in the past, such as sulfites or MSG.

The danger of providing an inadequate supply of oxygen to your baby is a much greater risk than taking the commonly used asthma medications.

Can any of the medications I take for my asthma cause harm to my baby?
Most medications used to treat asthma appear to be safe, especially those that have been around for many years and have been time tested. Unfortunately, it is difficult to conduct adequate studies in pregnant women to prove the safety of drugs.

Since we cannot prove the safety of drugs taken during pregnancy, should I stop taking my asthma medication as soon as I discover that I have become pregnant?
No. A moderate to severe asthma attack is a risk to both you and the baby. The risks of stopping your medication are far greater than any potential medication-related risk to your baby. Therefore, do not stop your regular asthma medication unless your doctor recommends it.

Are other medications taken for my hay fever or other allergies also safe?
Probably. However, some minor birth defects have been linked to certain antihistamines and decongestants in some studies, but study results have not been consistent. It would be best to call your physician before continuing antihistamines or decongestants, even those available over the counter.

If I become short of breath, how can my doctor know if my baby is getting sufficient oxygen?
There are tests that can accurately assess the breathing status of the mother, such as spirometry, arterial blood gases, or pulse oximetry. Ask your doctor about using an inexpensive portable peak flow meter with which you can assess changes in the severity of your asthma at home before you get into trouble.

Are there any medications that should be avoided during pregnancy?
Unless a life-threatening illness dictates their need, the following medications should be avoided during pregnancy, either entirely or during early or later stages:

  • Sulfonamides (the “sulfa” drugs) are safe early in pregnancy, but their use in the last trimester might result in a jaundiced infant.
  • Tetracyclines may cause skeletal and dental deformities.
  • Iodine-containing drugs used as expectorants can result in serious thyroid disease in the newborn.

Should I continue my allergy shots during pregnancy?
It is appropriate to continue allergy shots during pregnancy in women who are not having reactions to the shots, because they may lessen your allergic or asthma symptoms. There is no evidence that they have any influence on preventing allergies in the newborn. However, it is not generally recommended that allergy shots be started during pregnancy.

It is extremely important to monitor closely any asthma or allergic problems during your pregnancy. In the vast majority of cases, you and your child can look forward to a good outcome, even if your asthma is severe, so long as you follow your doctor’s instructions carefully. At the very first signs of breathing difficulty, call your doctor.


Source: American Academy of Allergy, Asthma & Immunology,

This article was originally published in Coping® with Allergies & Asthma magazine, Spring/Summer 2010.