The European Breast Milk Collection

Short- and long-term benefits of breastfeeding to both mothers and infants have been well demonstrated. However, robust clinical lactation studies are rare and existing data cannot be confidently translated into evidence-based clinical practice. In order to provide evidence for how a medicine transfers to breastmilk, we need to test milk from mothers who need treatment during the post-partum period. To that end, ConcePTION WP4 is developing a research infrastructure to collect, store and analyse samples of breast milk and blood. We are building a European self-sustaining breast milk and blood collection, referring both to the activity of collecting at various European sites, and the physical storage of samples.  

Want to know more? Have a look at this recorded presentation on the challenges of biobanking breast milk.

The European Breast Milk Collection is structured as follows: Uppsala Biobank is the storage facility that receives, stores and manages the breast milk collection; the Analytical Centre in Uppsala store results from pharmacokinetic analyses.

The infrastructure is compliant with regulatory quality and ISO standards, and will be a platform for lactation studies for both universities and pharmaceutical companies: Helping to bridge the knowledge gap for women who want to breastfeed and need information on drug transfer into breast milk. The breastmilk and blood collection will be self-sustaining and live on after the project ends, supporting research on medicines safety in breastfeeding in the future!

Five demonstration projects are being conducted to study milk transfer of Amoxicillin, Metformin, Prednisolone, Venlafaxine and Levocetirizine/cetirizine. The studies are carried out by different partners in the project and are intended to provide more information about the strength and feasibility of different methodological approaches. The results will inform our stakeholders (i.e., researchers in academic centers and industry, and regulators) about best practices for lactation studies. Samples will be collected on site, and shipped to the biobank in Uppsala, Sweden, where samples will also be analysed. Our ambition is to use these demonstration studies to provide researchers with adequate tools and analytical methods to carry out lactation studies and to set the standards at the European and international level.

Ongoing studies in Sweden

In Sweden, two demonstration studies are ongoing. We are currently collecting breast milk and blood samples from the mother and the child for metformin, which is used in the treatment of type 2 diabetes and prednisolone, which is used in the treatment of for example rheumatoid arthritis. In both cases, there is limited data, which is partly old, from the 1970s, and partly analyzed with outdated methods. Both studies are approved by The Swedish Medical Product Authority (MPA) as low intervention clinical trials.

Through these two studies, research biobanks with breast milk and associated blood samples are established for the first time in Sweden. In the long run, doctors and women who become pregnant can get better information for their recommendations and decisions regarding the use of medicines. 

The metformin study

The prednisolone study

A collaborative effort: The studies are a collaboration between Uppsala University and several clinical centres: Sahlgrenska University Hospital/East in Gothenburg, Örebro University Hospital, Center for Clinical Children’s Studies, Astrid Lindgren Children’s Hospital in Stockholm, Södra Älvsborgs Hospital in Borås and Umeå University Hospital, with adjacent biobanks.

Informed consent & protocol: Breast milk from the woman and blood samples from both woman and child will be transported to Uppsala Biobank for storage and analyzed with mass spectrometric methods at the Department of Pharmacy at Uppsala University. Informed consent is obtained both for the sampling and for the possibility of conducting future research on the stored samples.

Collaborating biobanks are: Uppsala Biobank, Biobank West in Gothenburg, Örebro Biobank, Stockholm Medical Biobank and Biobank North in Umeå. 


  • Approval demonstrations studies (2021-2023)
  • Plasma and breast milk sample collection (2021-2024)
  • Bioanalysis (2021-2024)
  • Modelling (2022-2023): to describe drugs’ disposition within mothers’ population; to identify covariates contributing to the population variability;
  • ConcePTION database (2023)
  • Share best practice (2024): SOP, publications, recommendations;
  • Develop and launch sustainability plan (2024)


Study leaders

Role of the breast milk collection in ConcePTION

European Breast Milk Collection at Uppsala Biobank

Analytical centre

Completed studies

We have completed a study on Levocetirizine/Cetirizine. More information about the study (in Norwegian) at