Asthma, Allergies and Pregnancy

Asthma Pregnancy

Note: The Pregistry website includes expert reports on more than 2000 medications, 300 diseases, and 150 common exposures during pregnancy and lactation. For the topic Asthma, go here. For the topic Allergic Rhinitis, go here. These expert reports are free of charge and can be saved and shared.


Women who are planning to have a family may want to review their allergy and asthma treatment plan with a healthcare provider. It’s important to keep allergies and asthma under control while you are pregnant. While most asthma medications can safely be used during pregnancy, some are preferable to others.

What can you expect while pregnant?

Pregnancy can change the intensity and frequency of allergy and asthma symptoms but just how that will happen can be hard to predict. About a third of all pregnant women see an improvement in asthma and allergy symptoms, a third see a worsening of symptoms and the remainder report no change at all. Women with severe asthma may be the most likely to see symptoms worsen during pregnancy, often during 29th to 36th week.

Why symptoms might worsen

One reason why some women’s allergies might worsen is that the rising hormones associated with pregnancy affect the sinuses and lungs. Approximately 30% of pregnant women report having a stuffy nose when they are pregnant, due to the fact that higher estrogen levels congest the tiny blood vessels in the nose. Higher levels of the hormone progesterone can cause women to breathe faster and feel out of breath. While this breathlessness is perfectly normal, it can potentially trigger an asthma attack.

Controlling symptoms as effectively and safely as possible may require a prescription review, but women are not advised to suddenly stop taking asthma or allergy medication.

Reviewing medication

Pregnancy is a time when women are naturally cautious about taking medication, but not adequately treating asthma or allergies may also pose risks. If a woman’s asthma is not controlled, her baby could be deprived of oxygen, which can lead to low birth weight and premature birth. The safest approach for mother and baby is talking to a healthcare provider about a treatment plan that uses the most thoroughly studied and safest medications.

Inhaled medications tend to be a preferred method of treating asthma during pregnancy because less of the medication winds up in the bloodstream. That includes some kinds of rescue inhalers, which are used to treat sudden asthma attacks, and some inhaled corticosteroids, which are used to treat patients who need daily anti-inflammatory medicine.

While nasal rinsing or breathing strips may help a stuffy nose, some antihistamines are also considered safe for use during pregnancy. Antihistamines might be recommended if a stuffy nose or any other allergic reaction interferes with eating or sleeping or triggers asthma.

Don’t start allergy shots

Allergy shots are a form of treatment in which the body becomes sensitized to an allergen through repeated injections of a small amount of the same allergen. Since the treatment can take years, women having this therapy may wonder if they should stop during pregnancy. That may not be necessary. If treatment has been underway for a while, without any adverse reaction, a woman can generally continue to receive treatment during pregnancy.

As safe as it might be to continue getting allergy shots, starting a new course of treatment during pregnancy is not recommended. Starting a new series of shots can potentially cause an allergic reaction known as anaphylaxis, which could be dangerous for mother and baby. In some cases of ongoing therapy, doctors prefer to lower the dosage for pregnant patients as a proactive measure.

Flu shots are recommended

Flu shots are already recommended for people who have asthma, so it’s even more important for pregnant women with asthma to safeguard against flu complications that can lead to respiratory infections and thereby trigger asthma.

According to the Centers for Disease Control, it is safe for pregnant women to get a flu shot during any trimester. A person with severe allergy to any vaccine component, including egg protein, should not get a shot at any time. Also, the nasal spray vaccine is not recommended for pregnant women.

GERD and asthma

Another issue that pregnant women with asthma may face is gastroesophageal reflux disorder or GERD, a digestive disease that causes acid reflux and can worsen asthma symptoms. To prevent heartburn, sleep with your head elevated, don’t eat a few hours before bedtime, and ask your healthcare provider about safe medication.

With the right treatment plan, there’s no reason that women with asthma or allergies should not have a safe and healthy pregnancy.

Joan MacDonald
Joan Vos MacDonald has written about health and fitness for newspapers, magazines and websites. She is a member of the National Association of Science Writers and the author of two books on health-related topics, "Tobacco and Nicotine Dangers," for young adults, and "High Fit Home," a design book about fitness and architecture. She lives in upstate New York near her children and grandchildren.

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