How breastfeeding works

J Midwifery Womens Health. 2007 Nov-Dec;52(6):564-70. doi: 10.1016/j.jmwh.2007.04.007.


Human milk is a complex secretion that is the sole ideal food for babies for at least the first 6 months of life. The amount and composition of the milk is largely independent of the mother's diet. The composition of the milk changes during lactogenesis II, and these changes can be used as biochemical markers of the onset of copious milk secretion. After 1 month of lactation, there are few further changes in the composition of milk until the volume of milk decreases substantially as the baby weans completely. The amount of milk produced depends on the amount of milk removed from the breast. Successful, exclusively breastfeeding babies show a three-fold variation in the amount of milk they take per day, and in the frequency of breastfeeds and amount of milk consumed during each breastfeed. The fat intake of the baby is independent of the feeding frequency. If a baby is growing normally, the mother can be confident that her baby does not need to follow prescribed breastfeeding regimes. She should respond to her baby's cues for the frequency of breastfeeds, and whether the baby requires one or both breasts for a meal. Continuing research into the physiology of breastfeeding provides a foundation for evidence-based treatment of breastfeeding difficulties.

Publication types

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

MeSH terms

  • Breast Feeding*
  • Female
  • Health Knowledge, Attitudes, Practice*
  • Humans
  • Infant, Newborn
  • Maternal Nutritional Physiological Phenomena*
  • Milk, Human / metabolism*
  • Mother-Child Relations
  • Prolactin / metabolism
  • Sucking Behavior / physiology*


  • Prolactin