HOW BREASTFEEDING WORKS

Abstract

Once you understand the physiology of milk production (lactation) and breast feeding it is very easy to work out how to help mothers prevent or overcome any problems they might have. Everyone knows that the hormonal changes of pregnancy and childbirth prepare and trigger the breasts to produce milk, but did you know that a woman can induce a milk supply even if she hasn't breast fed for many months or even years? Indeed, even a woman who has never been pregnant can stimulate her breasts to produce milk, though not enough to breast feed a baby fully. Pregnancy hormones set the stage for breast feeding by causing proliferation of the milk glands and ducts in the breasts. Each milk gland is surrounded by a fine network of blood vessels and it is through this blood supply that the hormones reach the milk‐producing cells. Blood also provides the materials from which milk is actually made by the cells. Prolactin is the main milk‐producing hormone and appears from the eighth week of pregnancy onwards, reaching its peak with the birth of the baby. It is prevented from producing milk in any volume during pregnancy by the high levels of oestrogen made by the placenta. After the baby is born and with the loss of the placenta, the oestrogen ‘brakes’ are removed and prolactin starts milk production in earnest. This usually occurs between the second and fourth days. The milk can come in earlier in women feeding their babies frequently and in those having their second or subsequent babies. The more stimulation of the breasts, the more milk is produced, probably by a simple nervous reflex pathway to and from the pituitary gland in the brain, which makes the hormones prolactin and oxytocin, responsible for milk production and letting down the milk, respectively.