The following is an excerpt from The American Academy of Family Physicians 2008 Position Paper on breastfeeding.
Note that breastfeeding at least until the second year of a child's life is not considered 'extended' breastfeeding. Rather, breastfeeding until the bare minimum age of 2 years is the norm and anything less brings about detrimental consequences. Human milk for growing human babies is expected (physiologically) by the baby's body in order to receive all that is needed (and only found in human milk) for this important period of rapid brain, body, and immune system development.
As recommended by the World Health Organization (WHO), breastfeeding should ideally continue beyond infancy, but this is not the cultural norm in the United States and requires ongoing support and encouragement. (1)
It is estimated that the natural weaning age for humans is between two and seven years. (2)
Family physicians should be knowledgeable regarding the ongoing benefits to the child of extended breastfeeding, including continued immune protection, (3) better social adjustment, (4) and having a sustainable food source in times of emergency.
The longer women breastfeed, the greater the decrease in their risk of breast cancer. (5)
Mothers who have immigrated from cultures in which breastfeeding beyond infancy is routine should be encouraged to continue this tradition. There is no evidence that breastfeeding beyond infancy is ever harmful to mother or child.
Breastfeeding during a subsequent pregnancy is not unusual and poses no risks. If the pregnancy is normal, and the mother is healthy, breastfeeding during pregnancy is a woman's personal decision.
If the child is younger than two years, the child is at increased risk of illness if weaned.
Breastfeeding a nursing child after delivery of the next infant (tandem nursing) may help provide a smooth transition psychologically for the older child. (6)
1) Scott JA, Landers MC, Hughes RM, Binns CW. Psychosocial factors associated with abandonment of breastfeeding prior to hospital discharge. J Hum Lact. 2001;17(1):24-30.
2) Powers NG, Slusser W. Breastfeeding update. 2: Clinical lactation management. Pediatr Rev. 1997;18(5):147-161
3) Dettwyler KA. A time to wean. In: Breastfeeding: Biocultural Perspectives. Stuart-Macadam P, Dettwyler KA, eds. New York, NY; Aldine De Gruyter, 1995:39-73.
4) Goldman AS, Goldblum RM, Garza C. Immunologic components in human milk during the second year of lactation. Acta Paediatr Scand. 1983;72(3):461-462.
5) Fergusson DM,Horwood LJ, Shannon FT. Breastfeeding and subsequent social adjustment in six- to eight-year-old children. J Child Psychol Psychiatr Allied Discip. 1987;28(3):378-386.
6) Lawrence RA, Lawrence RM. Breastfeeding: a guide for the medical professional. 6th ed. St. Louis: Mosby, 2005.
Review the full 2008 AAFP Position Paper on Breastfeeding here.