Asthma in Pregnancy

Pregnancy is an exciting time in a woman's life. Changes in your body may be matched by changes in your emotions. You don't know what to expect from day to day. You may feel tired, uncomfortable, or cranky one day and energetic, healthy, and happy the next. The last thing you need is an asthma attack.

Asthma is one of the most common medical conditions in the US and other developed countries. If you have asthma, you know what it means to have an exacerbation (attack). You may wheeze, cough, or have difficulty breathing. Remember that the fetus (developing baby) in your uterus (womb) depends on the air you breathe for its oxygen. When you have an asthma attack, the fetus may not get enough oxygen. This can put the fetus in great danger.

If you took medication for your asthma before you became pregnant, especially if your asthma was well controlled, you may be tempted to stop taking your medication out of fear that it might harm the fetus. That would be a mistake without the advice of your health care provider. The risk to the fetus from most asthma medications is tiny compared to the risk from a severe asthma attack. Moreover, women with asthma that is uncontrolled are more likely to have complications during pregnancy. Their babies are more likely to be born preterm (premature), to be small or underweight at birth, and to require longer hospitalization after birth. The more severe the asthma, the greater the risk to the fetus. In rare cases, the fetus can even die from oxygen deprivation.

How pregnancy may affect your asthma is unpredictable. About one third of women with asthma experience improvement while they are pregnant, about one third get worse, and the other third stay about the same. The milder your asthma was before pregnancy, and the better it is controlled during pregnancy, the better your chances of having few or no asthma symptoms during pregnancy.

If asthma control deteriorates during pregnancy, the symptoms tend to be at their worst during weeks 24-36 (months 6-8). Most women experience the same level of asthmatic symptoms in all their pregnancies. It is rare to have an asthma attack during delivery (10%). In most cases, symptoms return to "normal" within 3 months after delivery.

The important thing to remember is that your asthma can be controlled during pregnancy. If your asthma is controlled, you have just as much chance of a healthy, normal pregnancy and delivery as a woman who does not have asthma.

In pregnancy, just as before you were pregnant, you need an action plan for your asthma. Let your health care provider know as soon as you know you are pregnant. Together, the two of you should review your current action plan and make changes if necessary. You may find that your symptoms have changed, or that your sensitivity to certain triggers is different. Be sure to tell him or her all the medications you are taking, not just your asthma medications.

Symptoms of asthma during pregnancy are the same as those of asthma at any other time. However, each woman with asthma responds differently to pregnancy. You may have milder symptoms or more severe symptoms, or your symptoms may be pretty much what they are when you aren't pregnant.

In general, asthma triggers are the same during pregnancy as at any other time. Like the situation with asthma symptoms, during pregnancy sensitivity to triggers may be increased, decreased, or stay about the same. These differences are attributed to changes in hormones during pregnancy. Common triggers of asthma attacks include the following:

• Respiratory infections such as a cold, flu, bronchitis, and sinusitis: Both bacterial and viral infections can trigger an asthma attack.
  
  
• Cigarette smoke (firsthand or secondhand)
  
  
• Gastroesophageal reflux disease (GERD), or regurgitation of stomach contents up the esophagus or "food pipe" 
  
  
• Smoke from cooking or wood fires
  
  
• Emotional upset
  
  
• Food allergies
  
  
• Allergic rhinitis (hay fever or seasonal allergies)
  
  
• Changes in weather, especially cold, dry air
  
  
• Exercise
  
  
• Strong smells, sprays, perfumes
  
  
• Allergic reactions to certain chemicals
  
  
• Allergic reaction to cosmetics, soaps, shampoos
  
  
• Allergic reaction to irritants, such as dust/dust mites, molds, feathers, pet dander, etc.

If you have asthma and are pregnant, you should be extra vigilant about your symptoms. Keep in mind that your symptoms may be worse than usual. You may have an attack that is more severe than you are used to. Don't go by how your asthma has been in the past, go by your symptoms now. If you are having chest tightness or difficulty catching your breath, go to the nearest hospital emergency department. There you can be given oxygen and "rescue" medications that are safe for you and your baby. Do not plan to travel to remote areas with difficult access to health care facilities.

The best way to treat asthma is to avoid having an attack in the first place. Avoid exposure to your asthma triggers. This might improve your symptoms and reduce the amount of medication you have to take.

• If you smoke, quit. Smoking can harm you and your fetus. Avoid being around others who are smoking; secondhand smoke can trigger an asthma attack. Secondhand smoke also can cause asthma and other health problems in your children.
  
  
• If you have symptoms of gastroesophageal reflux (for example, heartburn), avoid eating large meals or lying down after eating.
  
  
• Stay away from people who have a cold, the flu, or other infection.
  
  
• Avoid things you are allergic to.
  
  
• Remove contaminants and irritants from your home.
  
  
• Avoid your known personal triggers (cat dander, exercise, whatever sets you off).

Asthma medications usually are taken in the same stepwise sequence you would take them in before pregnancy.

When your health care provider considers your use of a drug during pregnancy, he or she reflects on the following questions:

• Is the drug necessary?
  
  
• What information is available to assess the effect of the drug on the fetus?
  
  
• What is the effect of the drug on the pregnancy, including labor, delivery, and breastfeeding?
  
  
• Does the dose or dosing interval of the drug need to be altered because of the pregnancy?
  
  
• Do the risks of the drug outweigh the benefits?

We lack information on the effects of many drugs on the fetus. The US Food and Drug Administration (FDA) classifies drugs for use in pregnancy according to these categories:

• A - Safe in pregnancy
  
  
• B - Usually safe but benefits must outweigh the risks
  
  
• C - Safety for use during pregnancy has not been established
  
  
• D - Unsafe in pregnancy
  
  
• X - Contraindicated in pregnancy

A host of medications are listed in Category C because there is not significant study data about the medication in pregnancy. Several medications listed as Category C are generally regarded as safe, or safe during certain stages of pregnancy. You may need to discuss your medications and any concerns about them with your healthcare provider.

Most people with asthma take at least 2 medications: one for long-term prevention and control of asthma symptoms and one for quick "rescue" in case of an attack. The long-term medications are taken daily, even if there are no symptoms.

During pregnancy, inhaled corticosteroids are the mainstay for long-term control. Long-term medications are sometimes combined into single preparations, such as an inhaled steroid and a long-acting beta-agonist.

Rescue medications are taken only when symptoms appear. Inhaled short-acting beta-agonists are usually the first choice for fast relief of symptoms.

Control and preventive medications

Inhaled corticosteroids: Corticosteroids prevent symptoms by preventing the swelling and mucus secretion that go along with inflammation. They help prevent severe asthma attacks. They are the most popular long-acting asthma drugs for pregnant women because they work well and are considered to be safe in pregnancy. They cause few side effects. Examples include budesonide (Pulmicort) and beclomethasone (Vanceril, Beclovent, Qvar).

Leukotriene inhibitors: These drugs work by blocking a substance that is produced by cells in your body (leukotrienes) that causes swelling and spasm of airways. These drugs are considered safe during pregnancy, but in general they do not work for as many people as inhaled steroids. Examples are montelukast (Singulair), zafirlukast (Accolate), and zileuton (Zyflo).

Long-acting beta-agonist inhalers: These medications often are used in combination with inhaled steroids for severe or nighttime symptoms. They also are used to prevent exercise-induced asthma. Since their action is delayed, they are not used for rescue treatment (see short-acting beta-agonists below). Examples of long-acting beta-agonists include salmeterol (Serevent) and formoterol (Foradil).

Methylxanthines: These medications relax the airway walls. They have been linked to preterm labor, but in general they are thought to be safe in pregnancy. They are not used as much as the other long-term medications because they don't work for as many people. The most widely used example is theophylline (Slo-bid, Uniphyl).

Others: These medicines prevent swelling in the airway. They are used mostly to prevent attacks triggered by exercise, cold air, or allergies. They are considered safe in pregnancy, but they do not work in as many people as other long-term control medications. Examples include cromolyn (Intal) and nedocromil (Tilade).

Rescue medications

Short-acting beta-agonist inhalers: These inhaled medications quickly dilate the airways, relieving tightness, wheezing, and shortness of breath. They are relatively safe in pregnancy because only small quantities are absorbed into the bloodstream. These drugs generally have little negative effect on the fetus. An example is albuterol (Proventil, Ventolin).

Oral corticosteroids (taken as a pill): These medications are taken only for a short time until other medications begin to work and asthma is controlled. Their use during pregnancy is controversial, but the evidence points to their being safe. Examples include prednisone (Deltasone) and methylprednisolone (Medrol).

Anticholinergic agents: In inhaled form, these drugs are used in addition to a beta-agonist (or instead of a beta-agonist in people who cannot take beta-agonists) to relieve severe symptoms. An example is ipratropium bromide (Atrovent, Combivent).

Medications to avoid

Antihistamines and decongestants: These medications are used to relieve stuffy, runny, or itchy nose, itchy or watery eyes, and other minor allergy symptoms. Their safety in pregnancy is not known.

If possible, avoid regular use of epinephrine and other related medication (alpha-adrenergics) as they may pose a higher risk to the fetus. Epinephrine may be given as an injection to treat a severe asthma attack or a life-threatening allergic response. If this situation occurs, treating your reaction effectively and quickly is important to decrease the risk of oxygen deprivation to the fetus.

Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs): These medications are used to relieve headaches, muscle pain, inflammation, and fever. They are not recommended during late-term pregnancy.

If medications are needed to control GERD (heartburn), avoid regular use of antacids that contain bicarbonate and magnesium.

Flu shot: Also called the influenza vaccine, this shot can help prevent you getting the flu. The risk of severe asthma attack is very high if you get the flu. Because a severe asthma attack can deprive the fetus of oxygen, the shot is recommended in the second and third trimesters of pregnancy. (Its safety during the first trimester is more questionable.)

Allergy shots: If you took allergy shots before you became pregnant, and had no severe reaction to the shots, you should continue the shots during pregnancy. However, you should not start allergy shots during pregnancy.

Asthma attacks can have a number of negative effects on pregnancy outcome. Poor asthma control is linked to preterm birth, low birth weight, and stillbirths in the fetus and hypertension in pregnant women. Women who become pregnant while being treated for asthma should not stop using their medication unless they are specifically told to do so by their health care provider.

Media file 1: This graph shows asthma consensus guidelines used to manage chronic asthma. These guidelines are also generally used to treat pregnant patients with asthma.

Media type:  Graph

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Author: Irina Petrache, MD, Instructor, Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University.

Coauthor(s): Kathryn L Hale, MS, PA-C, Medical Writer, .com, Inc.

Editors: Ryland P Byrd Jr, MD, Chief of Pulmonary Medicine, Medical Director of Respiratory Therapy, Quillen VA Medical Center; Professor, Department of Internal Medicine, Division of Pulmonary Diseases and Critical Care Medicine, James H Quillen College of Medicine, East Tennessee State University; Mary L Windle, Pharm D, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Pharmacy Editor, .com, Inc; Zab Mosenifar, MD, Director, Division of Pulmonary and Critical Care Medicine, Executive Vice Chair, Department of Medicine, Cedars Sinai Medical Center, Professor of Medicine, University of California at Los Angeles School of Medicine.