There can be other factors such as Polycystic Ovary Syndrome for example.
In a recent casual survey of mothers (n=39) from two internet PCO support groups, 67% reported making enough milk while 33% had an insufficient supply. Of the poor production group, 67% produced very little at all. Interestingly, 1 out of 5 mothers in the sufficient supply group complained of problematic overproduction.
In the general population, it has been variously estimated that between 2 and 15% of all women are unable to produce enough milk. Most experts in the lactation field believe the percentage to be less than 5%.
There are several different ways that PCOS could potentially interfere with lactation. Breast development largely occurs during puberty and pregnancy as the result of estrogen, progesterone, and during pregnancy, prolactin. Estrogen mediates ductal growth, while progesterone mediates alveolar growth. It is well known that many if not all PCOS women are deficient in progesterone; depending upon the onset of PCOS, there is a hypothetical potential for disruption of alveolar growth during adolescence, not to mention during pregnancy.
In addition to the progesterone contribution to breast development, there are also the hormones estrogen and prolactin. While estrogen levels can be high in the peripheral tissues of some PCOS women, it has also been noted that androgens, which are generally high with PCOS, can down-regulate both estrogen and prolactin receptors. In essence, a woman could produce enough hormones but not have enough receptors to utilize them, thus limiting their influence upon breast tissue.
Another level of potential disruption lies in the lactation process itself. It is believed that the drop in progesterone at parturition serves to initiate production of mature milk. As this occurs, a process takes over which is driven by two major hormones, prolactin (affects production) and oxytocin (affects delivery). Prolactin receptors begin to develop during pregnancy, and then continue to multiply during the early postpartum period in proportion to the frequency of nipple stimulation. If receptor development was inhibited, the effectiveness of the circulating hormone would be diminished, thus limiting milk production.
Estrogen is a known inhibitor of milk production, especially in the early postpartum period. If the receptors are not down-regulated and the circulating estrogen levels are high, this too could potentially disrupt lactation.
Insulin also plays a vital, though less well-known, role in milk production. Women with uncontrolled diabetes mellitus will not make enough milk. Given this fact, what might be the effect of insulin resistance, which appears to be a significant factor in PCOS, upon lactation? The breast is a sensitive target organ for insulin; if insulin cannot be taken in quickly and efficiently enough, this too could hypothetically cause lactation problems.
The majority of the carbohydrate in human milk is in the form of lactose, which serves to enhance calcium absorption as well as provide a ready energy source for the rapidly growing infant brain. It is interesting to note that human babies make large amounts of lactase, enzymes which break down lactose, for the first couple of years of life, after which the production of these enyzmes diminishes greatly. This suggests that lactose is an important nutritional source for the human infant, but not for older humans.
Wet nurses are not available in every town.
Your comment below here is very interesting! I have read about native american supplementing by doing that. Mothers introduced solid food to the baby by chewing it first.
> PS: lets suppose a mother died and the infant only
>had a man there?
>Then the man probably would have ground up berries, fruit,
>or nuts, grains and made a watery mix to feed the baby.
>I have read about a few incidences of similar things
>among some 3rd world cultures, and also in other places
>in world in back history.
>Generally the man would chew up the stuff within his own
>mouth and spit small amts into the baby's mouth.
>An infant is born with a strong survival drive.
>With care, love, and nuturing a child will florish.
>Even in abusive environments,
>most infants will still grow,
>because of the instinct to survive.