Milk in Life Conditions (MiLC): Bacterial Composition of Human Milk Pumped and Stored in Real-Life Conditions

Study Overview
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Brief Summary
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The MiLC trial is a randomized control trial of two different breast pump set-ups: mother's own and sterile. The objective of this trial is to investigate the bacterial composition of human milk pumped and stored in real-life conditions. To meet this objective, lactating mothers will fully express breast milk from one breast on two consecutive pumping sessions at home, once with the participant's own pumps and collection kits (own pump set-up) and once with a hospital-grade pump and disposable, sterile collection kits (sterile pump set-up). Randomization will be used to determine which pump participants use first. From the total volume of milk pumped during each pumping session, the researchers will collect 1 oz. Milk from both pumps will be stored at home and sampled on days 0, 2, 4, and 30 after expression for analysis of its bacterial composition.

Detailed Description
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Participants will donate 1 oz of human milk during each of two consecutive pumping sessions, for a total volume of 2 oz donated on one day. To collect this human milk, participants will be asked to fully express one breast during each pumping session. Participants will pump once with the participant's own pump set-up and once with the sterile pump set-up (provided by the research team). Women will be randomized to which pump is used first. Randomization will be done using stratified randomization as follows: participants were stratified by how their infants were fed, namely whether infants were fed human milk only vs. human milk and complementary foods). Then, randomization was conducted within each strata. The researchers aim to have a minimum of 25 participants in each stratum. All human milk collections will occur at participants' homes between 0700 and 1100 hours. The second pumping session must begin 3 hours (+/-30 minutes) after the beginning of the first pumping session (e.g. the first pumping session at 7:30 am and the second at 10:30 am). Participants will elect from which breast to donate human milk and that breast will be used for both pumping sessions. Participants will be asked not to nurse from or pump that breast during the 2 hours before the first pumping session and not until after the second pumping session (a total of  5.5 hours). From the milk produced during each pumping session (which could be up to  6 oz), researchers will collect 1 oz using a sterile, plastic syringe. Participants will keep the remaining volume of milk. Each ounce of milk collected will be separated into 5 sterile containers (provided). Participants will store donated milk at home until it is picked up by a researcher 2, 4, and 30 days after pumping.

Official Title
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Milk in Life Conditions (MiLC): Characterizing the Bacterial Composition of Human Milk Pumped and Stored in Real-life Conditions

Conditions
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Human Milk Microbiome, Bacterial Growth

Intervention / Treatment
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* Device: Sterile pump set-up
* Device: Mother's Own pump set-up


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Lactating women over the age of 18 years Self-reported as healthy women and infants Use an electric breast pump Confident of ability to donate 1 oz of milk from one breast during each of two consecutive pumping sessions where pumping sessions are 3 hours (+/- 30 minutes) apart and between 0700-1100 hours. Able to store donated milk at home for 30 days Have infants who do not consume formula or only consume formula episodically as long as the most recent formula-feeding occurred > 2 weeks before the day milk is pumped for this study. Exclusion Criteria: Not confident of ability to donate 1 oz of milk from one breast during each of two consecutive pumping sessions, 3 hours (+/- 30 minutes) apart and between the hours of 0700-1100 hours. Infant consumption of formula in the past 2 weeks Current indication of breast infection (e.g., breast pain, discomfort, lumps, mastitis with fever, red streaks, or hard red portions of the breast) Breast pain that the woman does not consider normal for lactation/breastfeeding Signs/symptoms of acute illness in woman or infant in past 7 days including fever (rectal or temporal temperature ≥99.5 F), dark green nasal discharge, diarrhea (abrupt onset of 3 or more excessively loose stools in one day), vomiting (where infant vomiting is not associated with feeding), or severe cough.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: All participants will pump their milk with two pump set-ups: own and sterile supplies. The pump set-up each woman used first was randomized according to infant feeding status (human milk only vs. human milk and complementary foods).
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sterile pump set-up first<br>Participants will pump with sterile pump set-ups first. Approximately 3 hours later, participants will pump with their own pump set-ups. | Device: Sterile pump set-up<br>* Medela symphony breast pump (model number 0240108) and disposable, sterile collection kits (model number 67399S).<br>Device: Mother's Own pump set-up<br>* Mother's own electric breast pump and own collection kit (previously used and cleaned at home using her usual practices).<br>|
| Experimental: Mother's Own pump set-up first<br>Participants will pump with their own pump set-ups first. Approximately 3 hours later, participants will pump with sterile pump set-ups. | Device: Sterile pump set-up<br>* Medela symphony breast pump (model number 0240108) and disposable, sterile collection kits (model number 67399S).<br>Device: Mother's Own pump set-up<br>* Mother's own electric breast pump and own collection kit (previously used and cleaned at home using her usual practices).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bacterial Community Richness | Richness is the total number of different bacterial taxa detected in the sample. This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk. | 0 days after pumping | 
| Bacterial Community Diversity | Bacterial community diversity will be assessed using the the Shannon diversity index. The Shannon diversity index is a type of entropy measure and is a function of the distribution of the total number of organisms across all of the species. If S is the total number of species in the sample and p_i is the number of organisms in the i-th species divided by the total number of organisms, then Diversity = -Σ p_i log(p_i). This metric will be assessed on data collected via high-throughput sequencing of the bacterial 16S rRNA gene present in milk. | 0 days after pumping | 
| Total Live Aerobic Bacterial Counts | Number of live total aerobic bacteria in milk assessed by aerobic culturing of milk on plate count agar. Reported as colony-forming units (CFU)/mL. | 0 days after pumping | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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microbiome, human milk, breast milk, expressed human milk, bacterial communities, breast pump, bacterial growth