Recruiting

GLP-1 RA

Sponsor:

University of Colorado, Denver

Code:

NCT07720414

Conditions

Lactation

Weight Loss

Eligibility Criteria

Sex: Female

Age: 0+

Healthy Volunteers: Accepted

Interventions

Injected GLP-1 Receptor Agonists and Dual Agonists

Study Details

Brief summary:

There is increasing interest in using GLP-1 Receptor Agonist (GLP-1 RA) medications after pregnancy. This study is designed to determine if these medications affect breastmilk production or the nutritional makeup of breastmilk.

The main questions the study will address are:

  • Does GLP-1 RA-induced weight loss increase or decrease breastmilk production?
  • Does GLP-1 RA-induced weight loss affect the nutritional composition of milk, including milk fat content?

Researchers will assess milk production rates before and after mothers begin taking injected GLP-1 RA medications to decrease their body weight. Weight loss will be confirmed with 7-day body weight averages.

Participants will:

  • Weigh themselves and report measurements daily.
  • Participate in 2-3 morning study visits over approx. 2.5-4.5 months (approx. 3-3.5hrs each).

During each visit, participants will:

  • Use a study provided breastpump to express milk 3 times hourly for measurement of hourly milk production.
  • Provide 1-3 oz of milk for further study.
  • Answer questions about breastfeeding patterns.

Conditions

Lactation

Weight Loss

Study ID

NCT07720414

Start date

Jul, 2026

Status verified date

Jul, 2026

Completion date

Jun, 2028

Anticipated

Primary completion date

Jun, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 0+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • Breastfeeding mothers of single or multiple infants.
  • Milk removal at least 4x daily
  • Eligible for a GLP-1 RA administered subcutaneously (oral GLP-1 RAs contain absorption enhancers, which may drive accumulation in milk)
  • Access to a breastpump, if needed for maintaining breastfeeding behaviors.
  • Willingness to provide 1-3 oz of breastmilk per study visit.
  • Willingness to track and report body weight daily.
  • Willingness to maintain breastfeeding behaviors for the duration of the study.

Exclusion Criteria:

  • Currently taking GLP-1 RA medication or other weight loss medication
  • Induced lactation, due to unknowns regarding the durability of the mammary gland's milk production after exogenous stimulation.

Study Design

Enrollment

18 participants

Anticipated

Interventions and Outcome Measures

Arms

Breastfeeding mothers prescribed GLP-1 RA therapies

Breastfeeding mothers who have been prescribed, but have not started, an injected GLP-1RA (these patients have an indication for GLP-1 RA treatment (BMI ≥27 kg/m2 with at least one comorbidity (prediabetes, diabetes, metabolic syndrome, obstructive sleep apnea, hypertension, dyslipidemia, cardiovascular disease, heart failure, chronic kidney disease, metabolic dysfunction-associated steatohepatitis, atrial fibrillation, venous thromboembolic disease, osteoarthritis, polyendocrine metabolic ovarian syndrome), or BMI ≥30 kg/m2)) and who are committed to sustaining breastfeeding habits (frequency and volume of milk removal) for the duration of the study period.

Interventions

Injected GLP-1 Receptor Agonists and Dual Agonists

Participants are prescribed this medication by their care provider(s) as part of their postnatal clinical care, including but not limited to semaglutide and tirzepatide. The investigators do not provide, manage, or assign the medication.

Primary outcome measure

  • Hourly milk production rate [ Time Frame: From one week before until a maximum of 2 months after beginning GLP-1RA treatment. This timeframe will restart if their dosage is increased. ]
  • Milk macronutrient composition [ Time Frame: From one week before until a maximum of 2 months after beginning GLP-1RA treatment. This timeframe will restart if the dosage is increased. ]

Central Contacts and Locations

Central contacts

Jayne F Martin Carli, PhD

303-724-3981jayne.martincarli@cuanschutz.edu

Jacinda M Nicklas, MD, MPH

303-724-9028jacinda.nicklas@cuanschutz.edu

Locations

University of Colorado Anschutz School of Medicine

Recruiting

Aurora, Colorado, United States, 80045

More Information

Sponsor

University of Colorado, Denver

Last update posted

Jul 22, 2026

Last verified

Jul, 2026

Keywords

  • Breastmilk production
  • Breastmilk composition
  • GLP-1
  • Weight Loss

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Colorado, Denver on 2026-07-22.