Regulators, prescribers and patients are calling for initiatives to fill the knowledge gap about medicines and breastfeeding. The ConcePTION initiative set out to find out how safe medicines are for nursing mothers and their babies. A recent clinical lactation study, conducted within the framework of the ConcePTION project, set out to demonstrate the feasibility of a European collaborative human breast milk study by examining the transfer of a common antihistamine, cetirizine into breast milk. The results are detailed in a recent publication in Basic & Clinical Pharmacology & Toxicology, that sheds light on the safety of these medications during lactation.
Women sometimes choose to stop breastfeeding, or never start, because they fear the medicines they take will adversely affect their child. But breastfeeding benefits both mother and child, which is why it is important to study how safe medicines are for nursing mothers and their babies.
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 is developing a research infrastructure to collect, store and analyse samples of breast milk and blood. To construct 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.
To address this need, the ConcePTION project is diligently developing a European research infrastructure designed to collect, store, and analyse breast milk and blood samples – a self-sustaining system securely storing samples from various European locations. This also includes several demonstration studies, one of which is investigating the transfer of levocetirizine/cetirizine into breast milk. These studies, led by different partners within the ConcePTION project, seek to provide valuable insights into the efficacy and feasibility of various methodological approaches.
“The antihistamine cetirizine was an excellent candidate drug for us for several reasons. Firstly, only breast milk data from two women world-wide existed (!), so the knowledge gap was evident. Secondly, allergy is so frequent among breast feeding women, so the benefit of information for society would be huge, just to name a two reasons. Importantly, we demonstrated how a future system could work. We collected milk samples from women in Norway, shipped 188 breast milk samples to Sweden where they were analysed at Uppsala University and stored in the ConcePTION European Breast Milk Collection under the Uppsala Biobank, and discussed the results at the European level. This study demonstrated how we can work together in the future,” says Professor Hedvig Nordeng, primary investigator of the study and professor at the University of Oslo Norway.
So what were the results of the study? In brief, the study showed that cetirizine breast milk transfer and infant exposure via breast milk, was low, and confirmed that use of this medication against allergy was compatible with breastfeeding. The average cetirizine concentration in breast milk was 16.8 µg/L, the estimated absolute infant dose of 2.5 µg/kg/day, and the relative infant dose was less than 2%, which is considered insignificant. The study reported no severe adverse events related to cetirizine or levocetirizine use in breastfeeding women, further supporting the safety of these drugs during lactation.
In summary, the study suggests that cetirizine and levocetirizine can be considered safe for breastfeeding mothers, as their transfer into breast milk is minimal and unlikely to pose a significant risk to the nursing infant. However, as with all medications, individuals need to consult with their healthcare providers before using any medication while breastfeeding to ensure the safety and appropriateness of the specific drug for their situation.
By Anna Holm Bodin
Nordeng, H., Wegler, C., Lindqvist, A., Melander, E., Magnusson, M., Gandia, P., Panchaud., Baranczewski, P., & Spigset, O., (2023) Transfer of cetirizine/levocetirizine into human breast milk and estimation of drug exposure to infants through breastfeeding – a human lactation study from the ConcePTION project, Basic & Clinical Pharmacology & Toxicology, 9 October 2023, DOI: 10.1111/bcpt.13948