Full term breastfeeding (aka Natural weaning, Extended/Sustained breastfeeding or nursing)
[back] Breastfeeding  & Bottle-feeding

[Worldwide, the average age of weaning is 4 years.]

Extraordinary Breastfeeding by Veronika Robinson

Breastfeed a Toddler—Why on Earth? by Jack Newman, MD, FRCPC.

A Natural Age of Weaning by Katherine Dettwyler, PhD

Extend Breastfeeding's Benefits By Kyla Steinkraus

Sustained Breastfeeding by Kate Mortensen Grad Dip (Counselling), IBCLC, NMAA Counsellor

[pdf] Factsheet

Natural Weaning by Norma Jane Bumgarner

[pdf 1995] Weaning Ages in a Sample of American Women Who Practice Extended Breastfeeding----Muriel Sugarman, M.D.

See: American Academy of Pediatrics (AAP, Red Book Committee)

External
Ask Dr. Sears: Extended Breastfeeding -- Handling the Criticism

Breastfeeding: Are there health benefits in nursing past one year ... 

Extended Breastfeeding

Blogs about: Extended Breastfeeding

Book
Mothering Your Nursing Toddler by Norma Jane Bumgarner. 

Quotes
My research suggests that the normal and natural duration of breastfeeding for modern humans falls between 2.5 years at a minimum and about 7 years at a maximum. -----Katherine Dettwyler,

Breastfeeding for 2-4 years was the rule in most cultures since the beginning of human time on this planet. Only in the last 100 years or so has breastfeeding been seen as something to be limited. Children nursed into the third year are not overly dependent. On the contrary, they tend to be very secure and thus more independent. They themselves will make the step to stop breastfeeding (with gentle encouragement from the mother), and thus will be secure in their accomplishment. Jack Newman, MD, FRCPC.

In a group of 21 species of non-human primates (monkeys and apes) studied by Holly Smith, she found that the offspring were weaned at the same time they were getting their first permanent molars. In humans, that would be: 5.5-6.0 years.
2. It has been common for pediatricians to claim that length of gestation is approximately equal to length of nursing in many species, suggesting a weaning age of 9 months for humans. However, this relationship turns out to be affected by how large the adult animals are -- the larger the adults, the longer the length of breastfeeding relative to gestation. For chimpanzees and gorillas, the two primates closest in size to humans and also the most closely genetically related, the relationship is 6 to 1. That is to say, they nurse their offspring for SIX times the length of gestation (actually 6.1 for chimps and 6.4 for gorillas, with humans mid-way in size between these two). In humans, that would be: 4.5 years of nursing (six times the 9 months of gestation).
3. It has been common for pediatricians to claim that most mammals wean their offspring when they have tripled their birth weight, suggesting a weaning age of 1 year in humans. Again though, this is affected by body weight, with larger mammals nursing their offspring until they have quadrupled their birth weight. In humans, quadrupling of birth weight occurs between 2.5 and 3.5 years, usually.
4. One study of primates showed that the offspring were weaned when they had reached about 1/3 their adult weight. This happens in humans at about 5-7 years.
5. A comparison of weaning age and sexual maturity in non-human primates suggests a weaning age of 6-7 for humans (about half-way to reproductive maturity).
6. Studies have shown that a child's immune system doesn't completely mature until about 6 years of age, and it is well established that breast milk helps develop the immune system and augment it with maternal antibodies as long as breast milk is produced (up to two years, no studies have been done on breast milk composition after two years post partum).
And on and on. The minimum predicted age for a natural age of weaning in humans is 2.5 years, with a maximum of 7.0 years.   A Natural Age of Weaning by Katherine Dettwyler, PhD

The health benefits of extended nursing are impressive enough for the World Health Organization’s Innocenti Declaration  to recommend breastfeeding for up to two years and beyond for infants worldwide.......Extended nursing is so unusual in our culture that women may receive a great deal of criticism for continuing to nurse. While extended nursing is uncommon in our culture, it is not unusual from a global perspective, and is more in line with the recommendations of the World Health Organization than are the early weaning ages that are more typical among North American mothers. Upon encountering mothers who are nursing past infancy, it is important to bear in mind that the criticisms these mothers receive are based on cultural preference rather than scientific data. No empirical study to date has demonstrated that extended nursing is harmful, but a number of previously cited studies have found benefits. Therefore, practitioners can be confident in supporting mothers who choose to nurse their children into toddlerhood and beyond. [pdf 1995] Weaning Ages in a Sample of American Women Who Practice Extended Breastfeeding----Muriel Sugarman, M.D.

In the media frenzy around the publicity, there were many factual errors. The Daily Mail, to whom I gave an interview, fabricated quotes left, right and centre and in one particular quote, wrote the exact opposite of what I said. They hounded me for a family photo on the day of my mother in law's funeral. Not only was my story fabricated, but the other two women involved also had their stories altered in favour of how the Daily Mail thinks their stories should be! In Sophie's case, they stated (wrongly) that breastfeeding caused the break-up of her first marriage.  I also gave an exclusive interview to NOW magazine by email, but they too, sadly, managed to misquote and change the tone of what I said, despite it being written in black and white. Extend Breastfeeding's Benefits By Kyla Steinkraus

Babies tend to be loathed by many people, especially where rigidity in childcare has been well established for several generations. It seems likely that the presence of a baby stirs up feelings of a sad period in our own lives and we can project that onto the baby. People in western society get angry or upset when they think a baby is dominating the attention of an adult, perhaps because it unconsciously reminds them of their own inability to get their needs met as a baby. The 'loud noise at one end and no sense of responsibility at the other' definition of a baby denies the vulnerability of a new child. Similar factors may influence the rates of post-natal depression. Post-natal depression is considered by some to be hormonal in origin, yet why the hormonal state is assumed to precede the emotional state is unexplained. .....It is so evident in those societies where babies are nurtured, never left to cry and breastfed whenever they ask, that not only are the babies far more socially pleasing in that they are more content and alert, but also that adults in those societies do not view babies with the alarm and revulsion that so many people show in my own society. Also, where babies are cherished, children usually appear better socially integrated than in some western societies. One rarely meets the whining 'brat' who so often justifies the exclusion of children from adult company. The extremes of bitchiness and horror shown by some adults' over-attention to a baby is more than cultural habit; it has some deeper emotional cause. The Politics of Breastfeeding by Gabrielle Palmer

Breastfeeding in industrialised society is closely bound up with perceptions of sexuality. The very reason it is frowned upon in public is that breasts are perceived exclusively as objects of sexual attention. The extremity of this attitude was brought home to me when a male friend, responding to my statement that I could not see any good reason for women not being able to leave their breasts showing, stated that after all men did not walk about with their penises hanging out.The Politics of Breastfeeding by Gabrielle Palmer

The fact that such abhorrence is absent in some other societies may have another foundation. Few of us in industrialised society can remember suckling our own mothers. Many women have denied themselves the experience of reproduction because they know what a handicap it can be in the economic and career stakes. Others have children but do not breastfeed for the same, reason or because it went wrong in the hopelessly unsupportive medical and social systems. When we see a suckling pair it does not summon up associations of tenderness and pleasure, but of rejection, failure and pain both in our relationships with our own mothers and with our babies if we have them. Men who are jealous of their partners' breastfeeding may have had damaged feeding relationships with their own mothers and seeing the same scene in public may be too inexplicably painful. Women who have not fed their own children, especially if they had wanted to, may feel terrible seeing a breastfeeding pair. My sister taught me this when she admitted how angry she felt whenever she saw a breastfeeding couple. She could not feed her first baby because, as she realised when she was helped with her second, she had never been taught to position him properly. Until she understood her own experience better she had unconsciously projected her anger at failure, and betrayal by those who should have helped her, on to other, luckier women.The Politics of Breastfeeding by Gabrielle Palmer

By the twentieth century breastfeeding in much of western Europe and North America was quite different behaviourally from what it had been and what it still is in the areas of the world where it has not been disrupted. As the 'men of sense' (see page 41) took over the management from women, new ideas came into vogue. First came the limiting of feeds to an ideal of not more than five times a day, the prohibition of night feeding and then a limiting of the actual feed times. Only someone who did not spend twenty-four hours a day with a baby could have thought of restricting feeding time. These ideas had arisen from the dread of overfeeding, but they actually caused the problem of under­feeding, as the baby was prevented from stimulating the amount of milk she actually needed. Consequently there was a greater requirement for supplements which in turn decreased the baby's control of the breast milk supply. The discouragement of sleeping with the baby at night, which had been the norm since the dawn of human life, spread throughout the nineteenth century. In England, the early twentieth century health visitors zealously handed out banana boxes (available via cheap colonial labour) to serve as cradles in order to try and stamp out the habit of mothers and babies sleeping together. This was to prevent overlaying, supposedly a common cause of infant death, though this is debatable. Such deaths are unreported in those countries where it is still custom for babies and mothers to sleep together. What this separation did do was increase the risk of infant hypothermia, maybe cot (crib) death and lessen the important contraceptive protection of night suckling which is crucial for the maintenance of the frequent nipple stimulation necessary to maintain anovulation. A mother sleeping with her baby in her arms might not even be awakened, but that occasional mouthing is an important contraceptive. With these reductions in suckling time and the increasing promotion and use of other infant foods, mothers were truly breastfeeding less and less. Even the use of a dummy or boiled water given by spoon can reduce the nipple stimulation needed to maintain infertility.The Politics of Breastfeeding by Gabrielle Palmer