Medicines in Breast Milk and Estimated Infant Exposure

NCT07346716 | Recruiting

• 1 other identifier: H-23062687
• Study Type: observational
• Target: 250
• Locations: 1 country
• Sites: 3

Brief Summary

The MedMilk (Medication concentrations in human Milk) study investigates how selected medicines taken by breastfeeding women are transferred into human milk and whether this may affect the breastfed child. The study includes breastfeeding women who are already using prescription or over-the-counter medicines as part of their usual care. Participants provide samples of breast milk and urine and complete a questionnaire about maternal and infant health. The collected data will be used to quantify medicine concentrations in milk and estimate the relative infant dose. The study aims to contribute new data to support safer prescribing and more informed counselling during breastfeeding

Conditions

Breastfeeding; Medication Safety; Lactation; Drug Exposure Via Breast Milk; Pharmacokinetic Parameters

Keywords

breastfeeding; lactation; drug transfer into breast milk; medication safety

Outcome Measures

Primary Outcomes (1)

• Drug concentrations in human milk

  Quantification of drug concentrations in human milk, expressed in micrograms per millilitre (µg/mL). Milk samples are collected before and after the maternal dose within one dosing interval.

  Within one dosing interval

Secondary Outcomes (2)

• Relative Infant Dose (RID)

  Within one dosing interval

• Maternal-reported infant adverse effects

  At the time of inclusion. Montly follow-up for three months.

Other Outcomes (3)

• Simulated infant plasma levels

  During one dosing interval

• Simulated Area Under the Curve (AUC)

  During one dosing interval

• Biobank establishment

  Within one dosing interval

Study Arms (1)

Breastfeeding women on medication

Drug: Prescription Drugs

Interventions

Prescription Drugs DRUG

Exposure to prescription medicines taken by breastfeeding women during routine treatment. The study does not assign medications but observes drug transfer into human milk from exposures occurring as part of usual care.

Breastfeeding women on medication

Eligibility Criteria

• Age: 18 Years+
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Participants will be lactating women recruited through obstetric, neonatal, and psychiatric departments, public health visiting nurses, and counselling services across Denmark. Recruitment will be coordinated by the Department of Clinical Pharmacology, Bispebjerg and Frederiksberg Hospital, Copenhagen. The study primarily targets women using prescription and over-the-counter medicines during breastfeeding and aims to represent real-world exposure patterns across all Danish regions.

You may qualify if:

• Lactating women aged ≥18 years
• Current use of one or more prescription or over-the-counter (classified within the ATC system) drugs
• Able and willing to provide written informed consent

You may not qualify if:

• Current pregnancy during sample collection
• Known and clinically significant pharmacokinetic drug-drug interactions at the time of sampling

Sponsors & Collaborators

• University Hospital Bispebjerg and Frederiksberg: lead

Study Sites (3)

Department of Clinical Pharmacology

Copenhagen, Denmark

RECRUITING

Mental health services, Capital Region of Denmark

Copenhagen, Denmark

RECRUITING

Department of Obstetrics and Gynecology, Herlev Hospital

Herlev, Denmark

RECRUITING

Biospecimen

Retention: SAMPLES WITHOUT DNA

breast milk urine

MeSH Terms

Conditions

Breast Feeding

Interventions

Prescription Drugs

Condition Hierarchy (Ancestors)

Feeding Behavior; Behavior

Intervention Hierarchy (Ancestors)

Pharmaceutical Preparations

Study Officials

• Jon Traerup Andersen, Professor, MD, PhD

  Department of Clinical Pharmacology, Bispbjeg and Frederiksberg Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ditte Resendal Gotfredsen, MD

CONTACT

+4521472051; ditte.resendal.gotfredsen@regionh.dk

Jon Traerup Andersen, Professor, MD, PhD

CONTACT

jon.thor.traerup.andersen@regionh.dk

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor, PhD,

Study Record Dates

• First Submitted: December 8, 2025
• First Posted: January 16, 2026
• Study Start: December 20, 2024
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): January 1, 2030
• Last Updated: January 16, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, ICF
• Time Frame: Study protocol, SAP and ICF after protocol publication. Analytical code and summary results after completion of data collection and analyses.
• Access Criteria: Requests for data access can be directed to the principal investigator. Data sharing will require relevant approvals under Danish GDPR.

Locations

DK (3)