The information provided below is for readers based in the United States of America. Readers outside of the United States of America should seek the information from local sources.

What is asthma?

Asthma is a chronic disease that affects the lungs in pregnant women the same way it does in non-pregnant women. The airways in the lungs become inflamed, narrow and swollen, and produce extra mucus, making it difficult to breathe.

The airways in the lungs are a network of tubes that move air in and out of the lungs. When a person is exposed to an asthma trigger like cold air, tobacco smoke, or allergens, the muscles around the airways tighten and narrow the airways. Swelling of the airways and increased mucus make airways even narrower. All of these events lead to the symptoms of asthma.

How common is asthma during pregnancy?

It is estimated that 18.7 million US adults have asthma. It affects 4-8% of all pregnancies and is the most common lung disease managed during pregnancy.

How is asthma during pregnancy diagnosed?

The diagnosis of asthma is made the same way in pregnant women as it is in non-pregnant women. Asthma symptoms can differ greatly between people but generally includes at least one of the following:

  • Cough – especially at night or early morning, or related to exercise; people dont tend to bring up mucus with the cough (dry cough)
  • Episodes of wheezing – whistling or squeaky sound made during breathing
  • Feeling short of breath or having difficulty catching your breath
  • Chest tightness – this sometimes feels like something is sitting on your chest so you cant take a deep breath

Most people with symptoms of asthma notice a pattern to their symptoms that tends to be related to triggers, such as allergens (pollen, cat or dog hair, dust, etc.), exercise, or respiratory infections.

It can sometimes be difficult to diagnose asthma in pregnancy because breathing discomfort is a common symptom in normal, healthy pregnancies. In these circumstances, lung function tests, physical exams, and history may be used to make the diagnosis.

Does asthma cause problems during pregnancy?

Whether or not asthma causes problems during pregnancy depends on how severe a womans asthma symptoms are. Women who have mild or well-controlled moderate asthma have excellent pregnancy outcomes. Women with severe or poorly controlled asthma tend to have more pregnancy complications. These complications may include an increase in the following:

  • Cesarean delivery
  • Preeclampsia – a disease of pregnancy that causes high blood pressure with signs of kidney damage or other organ damage, like the liver, lung, or central nervous system
  • Postpartum hemorrhage – higher than average bleeding after delivery that usually requires treatment to decrease the bleeding
  • Miscarriage
  • Blood clot in the lungs
  • Depression

Does asthma during pregnancy cause problems for the baby?

Severe asthma and poorly controlled asthma increase the chances of delivering the baby before 37 weeks of pregnancy (a premature delivery) and having a poorly developed baby. There is also a small increase in the number of babies born with a cleft lip (an abnormal split in the upper lip) and/or a cleft palate (an abnormal split in the roof of the mouth) and the number of babies who die, whether or not the pregnant woman is taking any asthma medications.

What to consider about taking medications when you are pregnant or breastfeeding

  • The risks to yourself and your baby if you do not treat your asthma
  • The risk of getting severe or poorly controlled asthma if you stop taking your medication or if you switch to a different medication
  • The risks and benefits of each medication you use when you are pregnant
  • The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat asthma during pregnancy?

Asthma in pregnancy is classified by its severity, which is determined by how often a woman gets symptoms during the daytime and nighttime and lung function testing. Asthma severity is classified as follows:

  • Intermittent (well-controlled) – experience symptoms 2 days per week or less, waking up fewer than 2 nights per month with symptoms, does not limit activity, FEV1 > 80% (FEV1 is a measure of how well the lungs are working)
  • Mild persistent (not well controlled) – experience symptoms more than 2 days per week but not daily, waking up more than 2 nights per month with symptoms, has minor effect on activity, FEV1 > 80%
  • Moderate persistent (not well controlled) – daily symptoms, waking up at night at least once per week with symptoms, some activity limitation, FEV1 60-80%
  • Severe persistent (poorly controlled) – symptoms throughout the day, waking up 4 or more times per week with symptoms, extremely limited activity, FEV1 less than 60%

The severity of a pregnant womans asthma determines what medications are used to treat it. The goal of treatment is to limit the number of severe asthma episodes a mother has because each episode deprives the developing baby of necessary oxygen. This affects how well the baby is able to develop and leads to the complications discussed above.

Who should NOT stop taking medication for asthma during pregnancy?

During pregnancy, one-third of pregnant women will have worsening of their asthma, one-third will have it improve, and one-third will remain the same. All women whose asthma is the same or worse during their pregnancy should not stop taking their medication. Women who experience an improvement in their symptoms may be able to decrease or even stop some or all of their medications. However, this should be done under direct supervision from your caregiver after you have discussed this with them.

What should I know about choosing a medication for my asthma during pregnancy?

You may find Pregistry’s reports about individual medications to treat asthma here. Additional information can also be found in the sources at the end of this report.

All of the following asthma medications have been used in pregnancy and are considered safe for use during pregnancy:

Oral steroids, like prednisone, have been linked with an increased risk of cleft lip with or without cleft palate when they are used during the first 3 months of pregnancy. Since oral steroids are usually reserved for severe asthma, the benefits usually outweigh the risks. However, it is always important to ask your doctor if oral steroids are absolutely necessary and if there are any alternative treatment options.

There is limited information about salmeterol, formoterol, inhaled ipratropium, leukotriene receptor antagonists (like montelukast), and omalizumab. The little available information suggests that these medications are generally safe and not linked to any specific birth defects. It is currently advised that women who had good asthma control with any of these medications before their pregnancy continue to use them during their pregnancy to control asthma symptoms if they are needed.

Women who had been receiving allergen immunotherapy (allergy shots) to treat asthma before their pregnancy should continue with them during pregnancy. However, it is not recommended to start allergy shots during pregnancy because of the risk of severe allergic reactions that may occur when shots are first started.

What should I know about taking a medication for my asthma when I am breastfeeding?

The medications used to treat asthma are generally found in small amounts in breastmilk and are considered safe for use while breastfeeding. These medications include:

One positive benefit of breastfeeding is that it reduces the chances that your baby will develop childhood asthma, which may be another encouraging reason for asthmatic mothers to breastfeed.

What alternative therapies besides medications can I use to treat my asthma during pregnancy?

Many asthmatics have known triggers, like allergens or irritants. Knowing what these triggers are and taking steps to avoid them may help to reduce the need for medications. Common triggers that should be avoided are mold, dust mites, animal dander, and cockroaches. Avoiding exposure to tobacco smoke or quitting smoking can greatly improve symptoms.

Some women will develop asthma exacerbations from heartburn or gastroesophageal reflux, which are common in pregnancy. Alternative treatment for heartburn includes elevating the head of the bed, eating smaller more frequent meals, not eating within 2 hours of going to bed, and avoiding any known trigger foods or drinks.

What can I do for myself and my baby when I have asthma during pregnancy?

It is important to remember that keeping your asthma under good control is the one thing that you can do to ensure a healthy pregnancy. Continuing all necessary asthma medications is key to this.

If your doctor has not already given you a written action plan for your asthma, then you should discuss this with them. These are individualized plans that detail what triggers to avoid, what to do if your symptoms worsen, and when to call your doctor.

Resources for asthma during pregnancy:

For more information about asthma during and after pregnancy, call at 800-994-9662 (TDD: 888-220-5446) or read the following articles:

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Last Updated: 28-04-2020
General information

It is very common for women to worry about having a miscarriage or giving birth to a child with a birth defect while they are pregnant. Many decisions that women make about their health during pregnancy are made with these concerns in mind.

For many women these concerns are very real. As many as 1 in 5 pregnancies end in a miscarriage, and 1 in 33 babies are born with a birth defect. These rates are considered the background population risk, which means they do not take into consideration anything about the health of the mom, the medications she is taking, or the family history of the mom or the baby’s dad. A number of different things can increase these risks, including taking certain medications during pregnancy.

It is known that most medications, including over-the-counter medications, taken during pregnancy do get passed on to the baby. Fortunately, most medicines are not harmful to the baby and can be safely taken during pregnancy. But there are some that are known to be harmful to a baby’s normal development and growth, especially when they are taken during certain times of the pregnancy. Because of this, it is important to talk with your doctor or midwife about any medications you are taking, ideally before you even try to get pregnant.

If a doctor other than the one caring for your pregnancy recommends that you start a new medicine while you are pregnant, it is important that you let them know you are pregnant.

If you do need to take a new medication while pregnant, it is important to discuss the possible risks the medicine may pose on your pregnancy with your doctor or midwife. They can help you understand the benefits and the risks of taking the medicine.

Ultimately, the decision to start, stop, or change medications during pregnancy is up to you to make, along with input from your doctor or midwife. If you do take medications during pregnancy, be sure to keep track of all the medications you are taking.

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