Determination of prednisolone concentration in human breast milk and plasma of breastfed infants: study protocol of a Swedish multicentre low-intervention clinical trial.

INTRODUCTION

Many women need to use medications during breastfeeding. Very few medications have been adequately monitored, tested and labelled with safety information for this use. Prednisolone is one of these drugs. We aim to conduct a multicentre low-intervention clinical trial to determine the concentration of prednisolone in plasma of breastfed infants of lactating women treated with prednisolone. In addition, we will measure the concentration in maternal plasma and breast milk and calculate the daily infant dose (DID) and relative infant dose (RID). Infant cortisol levels will be analysed as a measure of clinical effects in the infants.

METHODS AND ANALYSIS

The study will be conducted at departments of obstetrics and gynaecology and specialist maternity and paediatric outpatient clinics in Sweden. We aim to include 30 lactating women treated with prednisolone and their breastfed infants. Breast milk and blood will be collected merely to study the secretion of prednisolone into breast milk and transfer to the infant. Participants will be treated with prednisolone according to their physician's prescription. Study visits take place when the infant is approximately 6-8 weeks old. Milk and blood sampling of the mother will be performed at 1 hour after drug intake, in conjunction with the infant being fed. Blood sampling of the infant will be performed 2 hours after the feed. Breast milk and plasma will be biobanked for future research. Recruitment was initiated in 2024 and is ongoing. Patient representatives from the Swedish Rheumatism Association were involved in the planning of the study, and the organisation is providing information about the study on their website.

ETHICS AND DISSEMINATION

The clinical trial was approved by the Swedish Medical Product Agency (Dnr. 5.1.1-2023-104170). The results will be published in peer-reviewed scientific journals and disseminated at scientific meetings and through patient organisations' websites.

TRIAL REGISTRATION NUMBER

The clinical trial protocol is available via the Clinical Trial Information System at the European Medicines Agency (No. 2023-508913-18-00). It is also registered and publicly accessible at the EU PAS Register (EUPAS 1000000059).