Overview

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.

Eligibility

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.