Medicine in the Milk - MedMilk

In MedMilk, we investigate how much medicine passes into breast milk and whether the children experience side effects

The Purpose of MedMilk

There is a significant lack of knowledge about how much and which medicines are excreted into breast milk. This is partly because pregnant and breastfeeding women are generally excluded from clinical trials. In fact, for more than half of the systemic medicines currently used by breastfeeding women, there is no information at all on transfer into breast milk and exposure of the infant. And for the remaining medicines, existing data are limited and often insufficient.

This lack of knowledge creates uncertainty for women and healthcare professionals and can lead to women stopping breastfeeding early, adverse effects in the infant, or interruption of necessary medical treatment.

We therefore aim to study how much medicine passes into breast milk in women receiving treatment. The results will strengthen counselling of mothers and make the use of necessary medicines during breastfeeding safer.

Safe breastfeeding and mental illness

One part of MedMilk, focuses on psychiatric medicines. Many women with mental illness need medication while breastfeeding. However, here too there is a significant lack of knowledge about how much medication is transferred to the infant via breast milk and whether this exposure is harmful to the child. This uncertainty forces many women to choose between medical treatment and breastfeeding—often in the absence of solid evidence about the actual risks.

Therefore, in this research project we investigate how much psychiatric medication is excreted into breast milk and whether it has adverse effects on the infant. The project aims to generate the necessary evidence to enable women to make safe, well-informed decisions for the benefit of both them and their child.

Target group

Breastfeeding women using psychiatric medication, such as antidepressants or antipsychotics.

Project relevance

The project will generate new, clinically relevant knowledge about the safety of using psychiatric medication during breastfeeding. This knowledge is currently lacking and will strengthen the evidence base for treatment decisions. The results can be applied directly in patient care, reduce uncertainty, and enable more women with mental illness to receive necessary treatment without having to discontinue breastfeeding.

Eligibility to participate:

You can participate in the study if you:
• Are over 18 years old
• Are breastfeeding
• Are taking medication