Asthma and Breastfeeding

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The information provided is taken from various reference sources.  It is provided as a guideline.  No responsibility can be taken by the author or the Breastfeeding Network for the way in which the information is used.  Clinical decisions remain the responsibility of medical and breastfeeding practitioners.  The data presented here is intended to provide some immediate information but cannot replace input from professionals.

Asthma inhalers – relievers or preventers – are safe to use as normal during breastfeeding.

Monteleukast can be used if needed. There is limited research but amount in breastmilk appears significantly lower than that licensed to be given to a 6 month old baby.

Prednisolone 40mg for 5 days is unlikely to affect the baby and breastfeeding can continue as normal.

Every ten seconds someone in the UK has a potentially life-threatening asthma attack and three people die every day. Tragically two thirds of these deaths could be prevented, whilst others still suffer with asthma so severe current treatments don’t work (

Many mothers have symptoms of asthma. We do not yet know the cause of asthma but there are genetic links and it is associated with exposure to cigarette smoke. One of the important ways to minimise asthma attacks (which are scary!) is to use prescribed medication regularly. Anecdotally some breastfeeding mothers have been avoiding using inhalers because they perceive a risk to their breastfed baby, particularly when using steroid (preventer) inhalers.

Asthma inhalers do not produce levels of drug in the blood system let alone in milk so are safe to use as normal during breastfeeding. They act locally in lungs to prevent or relieve symptoms.

Reliever inhalers – beta 2 agonist (often blue in colour)

Relievers are used when you have symptoms of wheeze or cough e.g. Salbutamol (Ventolin ®, Salamol ®, Airomir ®, Asmasal ® ), Formoterol (Atimos ®, Oxis ®), Terbutaline (Bricanyl ®), Salmetrol (Serevent®).

Preventer inhalers (often brown in colour) 

Preventer inhalers are usually steroids which reduce the inflammation in the lungs. They are added to reliever inhalers IF there is a need to use  an inhaled beta2 agonist three times a week or more, being symptomatic three times a week or more, experiencing night-time symptoms at least once a week, or if you have had an asthma attack in the last 2 years.  These inhalers are normally used regularly twice a day and it is good practice to rinse the mouth after use to avoid symptoms of oral thrush
e.g. beclomethasone (Asmabec®, Clenil®, Qvar®) , budesonide (Pulmicort®), fluticasone (Flixotide®), mometasone (Asmanex®).  

Compound inhalers 

Symbicort®(budesonide plus formoterol), Seretide®(fluticasone plus salmeterol) Fostair® (beclometasone plus formoterol). 

Inhaled long-acting beta2 agonist such as salmeterol and formetrol are usually only used if symptoms haven’t been controlled with short acting beta2 agonist plus steroid inhalers.

Leukotriene receptor antagonists

These are tablets added in if symptoms are not controlled, where asthma is exercise induced or where allergic rhinitis is an additional symptom to the asthma e.g. Montelukast (Singulair®), Zafirlukast (Accolate®).  We have one study of 7 women given monteleukast and the authors estimated the babies would receive 5.32 microgrammes per litre of breastmilk.  It is given directly to babies from 6 months of age at a dose of 4mg compared to an adult dose of 10mg (BNF).  However, in September 2019 the MHRA added a caution to use in children so individual mothers may need to decide for themselves if they wish to take this drug whilst breastfeeding.

Healthcare professionals are advised to be alert for neuropsychiatric reactions, including speech impairment and obsessive-compulsive symptoms, in adults, adolescents, and children taking montelukast.  The risks and benefits of continuing treatment should be evaluated if these reactions occur.  Patients should be advised to read the list of neuropsychiatric reactions in the information leaflet and seek immediate medical attention if they occur.” 

Acute asthma attacks

Acute attacks may necessitate use of a course of oral steroids, normally 40mg (8 x 5mg tablets) prednisolone.  These can be taken during breastfeeding without risk to the baby. Some authorities recommend waiting 4 hours after taking the once daily dose to minimise transfer but this is usually only necessary with doses in excess of 40mg (BNF).”

BTS/SIGN guideline for the management of asthma 2019 – section 12.5

Drug therapy for breastfeeding mothers

The medicines used to treat asthma, including steroid tablets, have been shown in early studies to be safe to use in breastfeeding mothers. There is less experience with newer agents. Less than 1% of the maternal dose of theophylline is excreted into breast milk (Turner 1980 )Prednisolone is secreted in breast milk, but milk concentrations of prednisolone are only 5–25% of those in serum. (Gibson 2003) The proportion of an oral or intravenous dose of prednisolone recovered in breast milk is less than 0.1% (Turner 1980) For maternal doses of at least 20 mg once or twice daily the nursing infant is exposed to minimal amounts of steroid with no clinically significant risk.

  • Encourage women with asthma to breastfeed.
  • Use asthma medications as normal during lactation, in line with manufacturers’ recommendations.


  • British National Formulary
  • Datta P, Felkins K, Baker T, Hale TW. Quantification of montelukast in breast milk. Texas Tech University Health Science Centre Research Day 2016: Amarillo, TX. Poster presentation April 13, 2016
  • Gibson PG, Henry RL, Coughlan JL. Gastrooesophageal reflux treatment for asthma in adults and children (Cochrane Review). In: The Cochrane Library, 2003.
  • Hale TW Medications and Mothers Milk 2016 (17th Ed) Hale publishing
  • Jones W Breastfeeding and Medication (Routledge 2013)
  • Lactmed database
  • NICE guideline [NG80] March 2021 Asthma: diagnosis, monitoring and chronic asthma management
  • SIGN158 British guideline on the management of asthma July 2019
  • Turner ES, Greenberger PA, Patterson R. Management of the pregnant asthmatic patient. Ann Intern Med 1980;93(6):905-18.

©Dr Wendy Jones MBE, MRPharmS and the Breastfeeding Network September 2021