World breastfeeding week: Medical cannabis considerations for mothers

What is World Breastfeeding Week?

World Breastfeeding Week is an international campaign, supported by the World Health Organisation (WHO) and UNICEF, as well as Ministries of Health and civil society partners around the world. The week-long event aims to raise awareness of the importance of breastfeeding in ensuring lifelong health and equity. 

World Breastfeeding Week 2025 runs from Friday the 1st to Thursday the 7th of August.

The health benefits of breastfeeding

Breastfeeding is considered the most effective way to ensure the long-term health and development of infants. Breast milk is not only suitable for meeting the child’s nutritional needs, but it also has unparalleled immunological and anti-inflammatory properties which may protect against a wide range of diseases and illnesses. 

For example, current literature indicates that children who are breastfed are significantly less likely to suffer from ear infections, lower respiratory infections, and even leukaemia, when compared to babies fed exclusively with formula. Moreover, many studies indicate that breastfeeding is associated with closer bonds between the mother and child, as well as improved health outcomes for the mother. 

Supporting mothers in their breastfeeding journey, including offering resources and advice on things to avoid when breastfeeding, is therefore vital. As we recognise Breastfeeding Awareness Week and the importance of breastfeeding for your child’s health and development, you might wonder: ‘Can I use medical cannabis when breastfeeding?’

Breastfeeding and medical cannabis use

Since the rescheduling of cannabis-based medicines in the UK in 2018, a growing number of patients have been able to access medical cannabis treatment for a wide range of conditions. 

Cannabis contains a huge number of active compounds, many of which have been found to possess impressive therapeutic potential. Cannabis-based medicines have become an increasingly popular option in the management of various conditions, including chronic pain, mental health disorders, and neurological conditions such as epilepsy and multiple sclerosis. 

Specialist doctors can consider prescribing medical cannabis in cases where at least two conventional therapies have proven insufficient in managing a patient’s condition or symptoms; however, there are some circumstances in which cannabis-based treatments are not considered suitable, including when the patient is pregnant or breastfeeding. 

Does cannabis affect breast milk?

Cannabis contains a huge number of active compounds, including cannabinoids. Many of these compounds have been found to possess impressive therapeutic potential, making cannabis-based medicines an increasingly popular option in the management of conditions including chronic pain, mental health disorders, and neurological conditions such as epilepsy and multiple sclerosis. 

However, current literature indicates that cannabis use may affect cognitive development, particularly in adolescents. Moreover, a one-year study, published in 1990, found that daily or near-daily cannabis use may impact the infant’s motor development, though occasional cannabis use was observed to have no discernable effects.

Several studies have found that active cannabis compounds, including THC (the most common psychoactive constituent of cannabis) is excreted in breastmilk in small quantities. While few studies have assessed in detail the risks associated with cannabinoid exposure through breastmilk, it is generally advised that breastfeeding mothers avoid cannabis use. 

Releaf’s stance on medical cannabis and breastfeeding

As standard, we do not prescribe medical cannabis to those who are pregnant, or currently breastfeeding as this is considered a contraindication to treatment. 

While there's limited evidence or research in relation to breastfeeding and medical cannabis, we feel it is always best to exercise caution. This stance is in line with general advice on the prescription of certain medications in the UK and around the world.

Of course, such advice is far from unique to cannabis-based medicines. In fact, many common medications are widely considered contra-indicated in breastfeeding. So, let’s take a look at some of these medications.

Breastfeeding and drug interactions

Breastfeeding mothers may be advised to avoid a number of common drugs due to the potential of exposure to the child through the breastmilk. Some of these medications include:

• Aspirin
• Codeine phosphate
• Oral decongestants (such as tablets, liquids, or powers)
• Some antidepressants and anti-anxiety medications
• Chemotherapy drugs
• Some anti-seizure medications (including Phenobarbital)

It is important to speak to a medical professional, including your GP, midwife, health visitor, or pharmacist, before taking a new medication or stopping taking a prescribed medication.

How do medications pass into breastmilk?

Virtually all drugs, prescribed and illicit, are transferred into breastmilk to some extent. However, in most cases, the detectable amount of the drug is usually too small to cause any adverse effects to the baby. Nonetheless, it is important to be aware of the potential of transfer and to follow the advice of your healthcare provider.

Studies have shown that drugs can enter breast milk through various pathways, the primary of which is passive diffusion. Moreover, drugs with a longer half-life (the time it takes for the amount of drug to reduce by half) are more likely to be detectable in breastmilk. 

Medical cannabis treatment post-weaning

Patients seek medical cannabis treatment for a huge variety of reasons, many of which may be applicable to new mothers. For example, cannabis-based medicines may be considered as a treatment for postpartum depression. Nonetheless, as part of our safety-first framework for prescribing, we can only consider approving treatment in such cases once weaning is complete. 

If you have recently finished weaning, or are in the process of doing so, and would like to learn more about medical cannabis treatment, our specialist prescribers are always on hand to help. Complete our online eligibility checker to find out if medical cannabis could be an option for you.