Montelukast During Pregnancy

Asthma is a common respiratory condition that makes it difficult to breath. Unfortunately, it is usually a chronic condition, which creates an ongoing need for proper management and treatment.

Now that you have discovered you are pregnant, you may wonder if it is safe to use montelukast during your pregnancy. Using montelukast, more commonly known as Singulair, during pregnancy is probably okay for your developing baby.

Below is information on Singulair use during pregnancy that you can review and use to help you have a more insightful discussion with your health care provider. It is always important to discuss any health concerns and medication use during pregnancy with your health care provider.

Montelukast and Pregnancy

  • Brand name: Singulair
  • Manufacturer: Merck & Co

Therapeutic Effect: Singulair is used to for the prophylaxis and chronic treatment of asthma in adults as well as children age 12 months and older. This medication is also used for prevention as well as exercise-induced bronchoconstriction in individuals 15 years of age and older. It is also indicated to relieve perennial allergic rhinitis in individuals 6 months of age and older and seasonal allergic rhinitis in individuals 2 years of age and older.

Pregnancy Safety Rating: Category: B

Pregnancy Recommendation: There is limited human data available. It is most likely compatible.

Side Effects:

Adults, children 15 yrs and older:

  • Frequent: (18 %) Headache.
  • Occasional: (4%) Influenza.

Pregnancy/Lactation Considerations: It is unknown if montelukast is distributed in breast milk. It is recommended to only use this medication during pregnancy if necessary.

Pregnancy Summaries:

The following summaries are cited directly from the sources of Briggs, Freeman, & Yaffe, the Physicians’ Desk Reference, and the Reprotox Toxicology Center.

Briggs, Freeman, & Yaffe – Montelukast is not teratogenic in animals, and few adverse outcomes in humans do not demonstrate a pattern that suggests a common etiology. One source states that montelukast may be safe to use during pregnancy, but this conclusion was based solely on animal studies (1).

A 2000 position statement of the American College of Obstetricians and Gynecologists and the American College of Allergy, Asthma and Immunology recommended that montelukast could be considered in patients with recalcitrant asthma who had shown a uniquely favorable response to the drug prior to becoming pregnant(2).

The available data supports this assessment. The manufacturer maintains a pregnancy registry for women exposed to montelukast. Health care professionals are encouraged to report pregnancy exposures to the registry by calling the toll free number 800-986-8999.

Physicians’ Desk Reference – There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, Singulair should be used during pregnancy only if clearly needed. For further information, please refer to the Physicians’ Desk Reference or contact your Healthcare Provider.

Reprotox Toxicology Center – Based on experimental animal data, montelukast is not expected to increase the risk of congenital anomalies. A registry including 203 exposed pregnancies has not identified a syndrome of abnormalities associated with montelukast exposure.

Limb reduction defects are now mentioned in the warning label for this drug because 6 cases have been collected in international reports. Available data do not establish a causative link between the drug and this class of congenital defects.

Next Steps:

If you are pregnant and have questions related to medication use during pregnancy, the Reprotox Toxicology Center is the most comprehensive and easiest to use resource on medication use during pregnancy.  You can subscribe for only $17.00 per month – Subscribe Now.

The American Pregnancy Association does not prescribe medication, nor do we serve as a consult for medication use during pregnancy.  It is imperative that you discuss the use of any medication during pregnancy with your health care provider.

The purpose of this document is to provide you with information to support discussions with your health care provider.


Hudgson, Barbara and Kizior, Robert, Saunders Nursing Drug Handbook 2012, Elsevier, St. Louis, MO. ISBN: 978-1-4377-2334-2.

Briggs, Gerald, Freeman, Roger and Yaffe, Sumner, Drugs in Pregnancy and Lactation, 9th Ed., Wolters Kluwer/Lippincott Williams & 3. Wilkins, Philadelphia, PA. ISBN: 978-1-60831-708-0, 2011.

Physicians’ Desk Reference (PDR), PDR Network, LLC, Motvale, NJ 07645 ISBN: 978-1-56363-780-3

Reproductive Toxicology Center,, agent # 4087