Comparison of the Patterns of Milk Ejection During Repeated Breast Expression Sessions in Women

Abstract

This study aimed to investigate the consistency of milk ejections and milk expression characteristics within mothers at repeated expression sessions. 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. 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. 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.