Physiological weaning

Weaning refers to the process of transferring the baby's dependence on the mom’s milk production to other sources of nutrition. Weaning is a complex process involving nutritional, microbiological and psychological adjustments – and it may occur at a different time point for everyone.

In general, babies show signs of being ready for solids in the second half of the first year of life. It is also nutritionally appropriate to begin feeding babies foods that contain iron from the age of six months. At this age, the requirement for iron exceeds the level that can be supplied by breast milk. Similarly, when babies are around twelve months old their protein requirement – to support rapid growth – increases and it cannot be met by breast milk alone.

Weaning may be baby-led, or mother-led. It can be described as the baby showing an increased interest in other foods and/or a decreased interest in breastfeeding. Reasons for weaning commonly cited by moms include the baby having lost interest in breastfeeding and not being satisfied by breast milk alone.

Physiological changes during weaning

Changes in milk composition and the mammary glands occur with weaning. Over a three-month period after weaning, milk volume decreases to approximately 67 per cent, 40 per cent and 20 per cent of baseline. During this time, the concentration of protein, sodium and iron increases by between 100 and 200 per cent, while lactose concentration decreases.

As milk is no longer removed from the breasts regularly, the glands become distended and milk production gradually decreases. The breasts become engorged with compression of the blood vessels, restricting blood flow and oxytocin to the myoepithelium. The alveoli are subsequently distended and flattened, and eventually collapse. The glandular tissue returns to a resting state and the amount of adipose tissue increases. The mammary glands at this stage revert to a near pre-pregnancy state, ready to undergo the same cycle of development when the next pregnancy occurs. The process of regression or involution during rapid weaning is likely to be very different from slow weaning over several months, but there has been little research in this area.

General guidelines for physiological weaning

  • It is recommended to gradually replace one feed at a time, which can later be increased so that a second feed is replaced at the opposite time of day (one morning and one night feed)
  • As solids are increased, breastfeeding on demand can still continue, although the feed duration and frequency may decrease
  • Solids should be given prior to a breastfeed while weaning
  • Weaning is both a physiological and emotional experience: it is normal for the mom to feel some depression or sadness at the reality of the last breastfeed

Lawrence, R. A. and Lawrence, R. M. Breastfeeding: a guide for the medical profession (Elsevier Mosby, Maryland Heights, MO, 2011).

Li, R., Fein, S.B., Chen, J., Grummer-Strawn, L.M. Why mothers stop breastfeeding: mothers' self-reported reasons for stopping during the first year. Pediatrics. 2008 Oct;122 Suppl 2:S69-76.

Garza, C., Johnson, C.A., Smith. E.O., Nichols. B.L. Changes in the nutrient composition of human milk during gradual weaning. Am J Clin Nutr. 1983 Jan;37(1):61-5.