Skip to main content

A new way of studying an old question – which medicines can be taken safely while breastfeeding?

Studies of medicines safety and breastfeeding often involve animals. Now IMI’s CONCEPTION project has a plan that could deliver better results while also using fewer animals.

Breastfeeding baby. Image by Alfonso Cerezo via Pixabay
Image by Alfonso Cerezo via Pixabay


Around 50 % of women who have just given birth need medication, yet we still lack information on which medicines can be safely taken while breastfeeding. This means that new mums who want to breastfeed but require medication for their own health often face a stark choice: breastfeed the baby and hold off on taking the medication, or take the medication and stop breastfeeding.

One of the aims of IMI’s CONCEPTION project is to deliver knowledge, tools and resources to plug this massive data gap so that breastfeeding women and their doctors can take an informed decision about whether or not it is safe to breastfeed while taking a given medication. As part of this effort, the project is collecting samples of milk from breastfeeding women who are using medicines. However, on its own, this is not enough, and so the project is investigating other ways of studying which medicines are likely to make it into breast milk.

Currently, three types of models are used to help answer this question. Firstly, there are in vitro models, which consist of cells in a dish or test tube. These allow scientists to assess how easily medicines are likely to make it into breast milk, and CONCEPTION is working to improve these models.

Secondly, there are computer based (‘in silico’) models which can also be used to predict the presence of a drug in breast milk. Here again, CONCEPTION is improving these models.

Finally, there are animal (in vivo) models, which are useful for analysing the mechanics of how a medicine makes it into the breast milk. CONCEPTION researchers recently published an extensive review of the pros and cons of different animals as models for research on breastfeeding.

So far, most research in animals has been carried out on rodents, as well as on animals like cows whose milk is drunk by humans. However, rodents and cows are very different from humans, meaning that results in these animals may not accurately predict what will happen in humans. Taking into account aspects such as similarity to humans, ethics and practical points such as the amount of milk produced, the team conclude that Göttingen Minipigs may be the most promising animal model for this research. Because they are bred for research purposes, Göttingen Minipigs are standardised and this means fewer animals are needed for experiments. From a practical and ethical standpoint, they are large enough for milk to be collected easily and without disturbing lactation or the growth of the piglets.

Ultimately, the CONCEPTION team believes that the best way of studying which medicines get into breast milk is to combine in vivo, in vitro and in silico models.

‘We believe it is even better to combine in vitro and in vivo data. This allows us to understand the mechanisms, and to learn how to apply data generated in cells to a living organism. At the same time this approach strongly reduces the number of animals needed,’ says Nina Nauwelarts of the KU Leuven Drug Delivery and Disposition Lab in a video made by the project. ‘The combination of different non clinical methods will enable us to predict medicine transfer into human breastmilk and subsequent infant exposure via breastfeeding. This information will allow physicians to give evidence based advice to women about the use of medicines during breastfeeding.’

How would combining approaches work in practice? ‘The approaches used are directly connected through a continuous flow of information,’ explains Alberto Elmi of the University of Bologna. ‘Moreover, both in vitro and in vivo data feed the mathematical approaches of the in silico platform, and this will further strengthen the other models. In addition, use of the human lactation data collected elsewhere in the project will allow us to validate the in silico, in vivo and in vitro platforms.’

CONCEPTION has incorporated the ‘3Rs’ (i.e. the reduction, refinement and replacement of animals in research) into its work from the very beginning. However, Dr Elmi highlights a 4th ‘R’: ‘In the project, a pivotal point is represented by transparency in animal data communication and ethics within the consortium, and the constant dissemination of results not only to the scientific community but also to the public. One of the milestones on which we are resting our communication strategies for the use of animals for experimental purposes is the fourth R: Responsibility.’


Find out more

Visit the CONCEPTION website

Read CONCEPTION’s news story ‘Developing a model for how medicines transfer to breast milk’

Watch CONCEPTION’s video on the models


Related projects: 

Manage your newsletter subscriptions
Stay informed - subscribe to our newsletter.