Asthma can be affected by the hormonal changes of pregnancy in various ways. Approximately one third of women get worse, one third improve, and one third notice no change in their asthma control. Monitoring of pregnant women with asthma is by symptoms and spirometry with measurement of FeV1. Poor asthma control during pregnancy may be associated with low birth weight and prematurity.

It is important for pregnant women to NOT discontinue their asthma treatment when they become pregnant. Most asthma therapy is safe during pregnancy, and a significant asthma attack may be more harmful for the fetus than asthma drug therapy. Gastro-esophageal reflux during pregnancy my aggravate asthma, and may require treatment.

 Asthma drug Safety
Short acting beta-agonists (eg. Ventolin, Bricanyl) Safe
Long acting beta-agonist (eg. Oxeze, Serevent) Safe (newer drugs, therefore less data)
Epinephrine Avoid for asthma in pregnancy
Inhaled steroids (eg. budesonide, fluticasone) Safe
Singulair (montelukast) Safe
Prednisone (or other oral/IV steroids) Small possible/theoretical risk, but commonly used in asthma during pregnancy if required.

An acute asthmatic attack in pregnancy requires prompt and aggressive treatment, with attention to oxygen supplementation. No change is necessary to the usual management approach (inhaled bronchodilators, systemic corticosteroids). Systemic epinephrine should not be used.

Suggested links:

NAEPP Working Group Report on Asthma and Pregnancy
ACOG Practice Bulletin, Asthma in Pregnancy, 2008

Special Pregnancy Program

Referrals »

Fetal Medicine: 416-586-4800 x 7756
Fax: 416-586-3216

Maternal Medicine: 416-586-4800 x 7000
Fax: 416-586-5109

Main clinic hours: Monday to Friday, 8am to 4pm

Prenatal Diagnosis & Medical Genetics

Referrals »

phone: 416-586-4800 x 4523
fax numbers:
416-586-4723 or 416-586-8384

Perinatal Mental Health

Referrals »

Phone: 416-586-4800 x 8325
Fax: 416-586-8596