Asthma Medication Safety During Pregnancy

Though no medication has been proven entirely safe for use during pregnancy, your doctor will carefully balance medication use and symptom control. Your treatment plan will be individualized so that potential benefits of medications outweigh the potential risks of these medications or of uncontrolled asthma.

Asthma is a disease in which intensity of symptoms can vary from day to day, month to month, or season to season regardless of pregnancy. Therefore, a treatment plan should be chosen based both on asthma severity and experience during pregnancy with those medications. Remember that the use of medications should not replace avoidance of allergens or irritants, as avoidance will potentially reduce medication needs.

In general, asthma medications used in pregnancy are chosen based on the following criteria:

Inhaled medications are generally preferred because they have a more localized effect with only small amounts entering the bloodstream.

Time-tested older medications are preferred since there is more experience with their use during pregnancy.

Medication use is limited in the first trimester as much as possible when the fetus is forming. Birth defects from medications are rare (no more than 1 percent of all birth defects are attributable to all medications).

In general, the same medications used during pregnancy are appropriate during labor and delivery and when nursing.

Bronchodilator medication

Inhaled beta2-agonists, often called “asthma relievers” or “rescue medications,” are used as necessary to control acute symptoms. Any of the short-acting beta agonists, including metaproterenol (Metaprel, Alupent), albuterol (Proventil, Ventolin), isoetharine (Bronkometer), bitolterol (Tornalate), pirbuterol (Maxair) and terbutaline (Brethaire) are considered safe in pregnancy. Albuterol, metaproterenol and terbutaline have been studied in humans. Injections of terbutaline are sometimes used to control premature labor.

A new long-acting inhaled beta agonist, salmeterol (Serevent), as well as older oral forms of albuterol (Proventil Repetab, Volmax) are available. No trials of these medications in pregnancy have been performed, and careful consideration is advised with use during pregnancy. These medications may be especially helpful for control of nighttime symptoms to ensure uninterrupted sleep.

Theophylline has extensive human experience without evidence of significant abnormalities. Newborns can have jitteriness, vomiting and fast pulse if the maternal blood level is too high. Therefore, patients who receive Theophylline should have their blood levels checked during pregnancy.

Ipratropium (Atrovent), an anticholinergic bronchodilator medication, does not cause problems in animals; however, there is no published experience in humans. Ipratropium is absorbed less than similar medications in this class, such as atropine.

Anti-inflammatory medication

The anti-inflammatory medications are preventive, or “asthma controllers,” and include inhaled cromolyn (Intal), nedocromil (Tilade), corticosteroids and antileukotrienes. These medications are recommended for all but mild intermittent asthma patients. Anyone requiring the use of beta2-agonists more often than three times a week, or have reduced peak flow readings or spirometry (lung function studies), usually needs daily anti-inflammatory medication. Inhaled cromolyn sodium is virtually devoid of side effects, but is less effective than inhaled corticosteroids. Nedocromil is a newer medication, similar to cromolyn. Although there is no reported experience with nedocromil during human pregnancy, animal data are reassuring.

Beclomethasone (Beclovent, Vanceril) is the inhaled corticosteroid of choice because of its length of time in clinical use and good safety profile in humans. Other drugs in this class, which have been available for a number of years, are triamcinolone (Azmacort) and flunisolide (Aerobid). There is limited data during human pregnancy for these drugs. Experience with the newest inhaled corticosteroids, fluticasone (Flovent) and budesonide (Pulmicort), is even more limited. Maximum benefits of all these inhalers may not be evident for several weeks.

In some cases oral or injectable corticosteroids, prednisone, prednisolone or methyprednisolone, may be necessary for a few days in moderately severe patients, or throughout pregnancy in severe cases. Some studies have demonstrated a slight increase in the incidence of preeclampsia, premature deliveries or low-birth-weight infants with chronic use of corticosteroids. However, they are the most effective drugs for the treatment of asthma and allergic disorders. Therefore, their significant benefit usually far exceeds their minimal risk.

Three antileukotrienes, zafirlukast (Accolate), zileuton (Zyflo) and montelukast (Singulair), are available. Results of animal studies are reassuring for zafirlukast and montelukast, but there are no data in human pregnancy with this new class of anti-inflammatory drugs.

Antihistamines may be useful during pregnancy to treat the nasal and eye symptoms of seasonal or perennial allergic rhinitis, allergic conjunctivitis, the itching of urticaria (hives) or eczema, and as an adjunct to the treatment of serious allergic reactions including anaphylaxis (allergic shock). With the exception of life-threatening anaphylaxis, the benefits from their use must be weighed against any risk to the fetus. Because symptoms may be of such severity to affect maternal eating, sleeping or emotional well-being, and because uncontrolled rhinitis may pre-dispose to sinusitis or may worsen asthma, antihistamines may provide definite benefit during pregnancy.

Chlorpheniramine (Chlor Trimeton), tripelennamine (Pyrabenzamine) and diphenhydramine (Benadryl) have been used for many years during pregnancy with reassuring animal studies. Generally, chlorpheniramine would be the preferred choice. A major drawback of these medications is drowsiness and performance impairment in some patients. Although there have been no reports of harm with the newer non-sedating drugs including astemizole (Hismanal), fexofenadine (Allegra), loratadine (Claritin), cetirizine (Zyrtec) or the nasal spray azelastine (Astelin), human data are very limited. Loratadine and cetirizine have reassuring animal study data and may be useful if older drugs cause performance impairment or excessive sleepiness.

The use of decongestants is more problematic. The nasal spray oxymetazoline (Afrin, Neo-Synephrine Long-Acting, etc.) appears to be the safest product because there is minimal, if any, absorption into the blood stream. However, these and other over-the-counter nasal sprays can cause rebound congestion and actually worsen the condition for which they are used. Their use is generally limited to very intermittent use or regular use for only three consecutive days.

Although pseudophedrine (Sudafed) has been used for years, and studies have been reassuring, there have been recent reports of a slight increase in abdominal wall defects in newborns. Use of decongestants during the first trimester should only be entertained after consideration of the severity of maternal symptoms unrelieved by other medications. Phenylephrine and phenylpropanolamine are less desirable than pseudophedrine based on the information available.

An anti-inflammatory nasal spray, such as cromolyn (Nasalcrom), or beclomethasone (Beconase, Vancenase), a corticosteroid, should be considered in any patient whose allergic nasal symptoms last for more than a few days. These medications prevent symptoms and lessen the need for oral medications. They have a record of use for many years. Newer corticosteroid sprays including triamcinolone (Nasacort, Tri-Nasal), fluticasone (Flonase), budesonide (Rhinocort), flunisolide (Nasarel) and mometasone (Nasonex) lack pregnancy data, although their absorption into the blood stream is so minimal as to be of doubtful risk.

Immunotherapy and influenza vaccine

Allergen immunotherapy (allergy shots) is often effective for those patients in whom symptoms persist despite optimal environmental control and proper drug therapy. Allergen immunotherapy can be carefully continued during pregnancy in patients who are benefiting and not experiencing adverse reactions. Due to the greater risk of anaphylaxis with increasing doses of immunotherapy and a delay of several months before it becomes effective, it is generally recommended that this therapy not be started during pregnancy.

Patients receiving immunotherapy during pregnancy should be carefully evaluated. It may be appropriate to lower the dosage in order to further reduce the chance of an allergic reaction to the injections.

Influenza (flu) vaccine is recommended for all patients with moderate and severe asthma. There is no evidence of associated risk to the mother or fetus.

Can asthma medications safely be used while nursing?

Nearly all medications enter breast milk, though infants are generally exposed to very low concentrations of the drugs. Hence, the medications described above rarely present problems for the infant during breast feeding. Specifically, very little of the inhaled beta agonists, inhaled or oral steroids, and theophylline will appear in mother’s milk. Some infants can have irritability and insomnia if exposed to higher doses of medication or to theophylline. Use of zafirlukast and zileuton while breast feeding is not recommended because of lack of data regarding safety. In general the lowest drug concentration in mother’s milk can be obtained by taking the necessary medications 15 minutes after nursing or three to four hours before the next feeding.


It is important to remember that the risks of asthma medications are lower than the risks of uncontrolled asthma, which can be harmful to both mother and child. The use of asthma or allergy medication needs to be discussed with your doctor, ideally before pregnancy. Therefore, the doctor should be notified whenever you are planning to discontinue birth control methods or as soon as you know that you are pregnant. Regular follow up for evaluation of asthma symptoms and medications is necessary throughout the pregnancy to maximize asthma control and to minimize medication risks.