Comparison of the patterns of milk ejection during repeated breast expression sessions in women

Breastfeed Med. 2011 Aug;6(4):183-90. doi: 10.1089/bfm.2011.0014.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Breast / metabolism
  • Breast / physiology*
  • Breast Feeding / methods*
  • Breast Feeding / statistics & numerical data
  • Breast Milk Expression / methods
  • Female
  • Humans
  • Lactation / physiology
  • Milk Ejection / physiology*
  • Milk, Human / metabolism*
  • Oxytocin / metabolism*
  • Suction / instrumentation
  • Time Factors


  • Oxytocin