title: Comparison of the patterns of milk ejection during repeated breast expression sessions in women.
abstract: BACKGROUND
  This study aimed to investigate the consistency of milk ejections and milk expression characteristics within mothers at repeated expression sessions.
  
  
  METHODS
  Twenty-five breastfeeding mothers expressed their breasts simultaneously on three occasions within 3 weeks, and follow-up visits were performed at 6, 9, and 12 months of lactation. During the 15-minute expression, milk was collected onto a continuous weigh balance to measure milk flow rate.
  
  
  RESULTS
  The number of milk ejections was similar at the three sessions (5.1±2.0), decreasing at the 12-month follow-up (3.3±1.2). Mothers had a similar pattern of milk ejection at each session. The time that each milk ejection occurred was consistent for the first 9 months of lactation. Of the four milk ejection patterns identified, each removed a similar percentage of available milk but varied in the time to reach 80% of the total expression volume. The first two milk ejections produced the greatest percentage (62%) of total milk volume during breast expression.
  
  
  CONCLUSIONS
  For each individual mother, the timing, pattern, and number of milk ejections were consistent, suggesting a predetermined release of oxytocin. In light of the innate oxytocin release and milk removal characteristics in women, there is potential for individual tailoring of the duration of expression.
authors.affiliation: School of Biomedical, Biomolecular, and Chemical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia . danielle.prime@gmail.com
authors.forename: Danielle K
authors.initials: DK
authors.lastname: Prime
authors.forename: Donna T
authors.initials: DT
authors.lastname: Geddes
authors.forename: Anna R
authors.initials: AR
authors.lastname: Hepworth
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Trengove
authors.forename: Peter E
authors.initials: PE
authors.lastname: Hartmann
mesh_terms: D000328:Adult; D001940:Breast / Q000378:metabolism / Q000502:physiology*; D001942:Breast Feeding / Q000379:methods* / Q000706:statistics & numerical data; D061186:Breast Milk Expression / Q000379:methods; D005260:Female; D006801:Humans; D007774:Lactation / Q000502:physiology; D008893:Milk Ejection / Q000502:physiology*; D008895:Milk, Human / Q000378:metabolism*; D010121:Oxytocin / Q000378:metabolism*; D013396:Suction / Q000295:instrumentation; D013997:Time Factors
chemical_list: D010121:Oxytocin