Beginninng lactation

When the baby sucks, a hormone called oxytocin starts the milk flowing from the alveoli, through the ducts (milk canals) into the sacs (milk pools) behind the areola and finally into the baby's mouth When the baby sucks, a hormone called oxytocin starts the milk flowing from the alveoli, through the ducts (milk canals) into the sacs (milk pools) behind the areola and finally into the baby's mouth,

Breast milk

Throughout pregnancy a woman's body produces hormones which stimulate the growth of the milk duct system in the breasts.

By the fifth or sixth month of pregnancy, the breasts are sufficiently developed to produce milk (although it is also possible to induce lactation as described in a later section). Near the time of birth, the breasts may begin to secrete a thick, yellowish fluid called colostrum (or "beestings"), which is the first milk the infant receives. It contains important antibodies from the mother's body providing "immunological protection." Colostrum has less fat and sugar than mature milk – these substances increase three to four days after birth when the suckling action of the infant further stimulates the breast to produce mature breast milk. Colostrum also contains more protein than mature milk.

After the colostrum the breast produces milk on a basis of supply and demand in response to how often a child feeds and how much milk he or she consumes. The production, secretion and ejection of milk is called lactation. Some breastfeeding advisers recommend at least one feeding every four hours to prevent premature termination of lactation.

The exact integrated properties of breast milk are not entirely understood, but the nutrient content after this period is relatively consistent and draws its ingredients from the mother's food supply. If that supply is found lacking, content is obtained from the mother's bodily stores. The exact composition of breast milk varies from day to day, depending on food consumption and environment, meaning that the ratio of water to fat fluctuates. Foremilk, the milk released at the beginning of a feed, is watery, low in fat and high in carbohydrates relative to the creamier hindmilk which is released as the feed progresses. The breast can never be truly "emptied" since milk production is a continuous biological process.

The let-down reflex

The let-down reflex, also known as the milk ejection reflex, is the stimulation of the muscles of the breast to squeeze out the milk by the release of the hormone oxytocin. Breastfeeding mothers describe the sensation differently, with some feeling slight tingling and others not feeling anything different.

The reflex is not always consistent, especially at the start of the breastfeeding process. The thought of nursing or the sound of any baby can stimulate the process, causing unexpected leakage. Commonly both breasts can give out milk when one infant is feeding, but this and other problems often settle after two weeks of feeding. One major cause of difficulties during breastfeeding is when the mother is in a stressed or anxious state of mind.

Benefits for the infant

Breast milk consumption has been linked to a decreased risk for several infant conditions including Sudden Infant Death Syndrome (SIDS). The sucking technique required of the infant encourages the proper development of both the teeth and other speech organs.

Numerous health benefits of breastfeeding have been medically documented. According to the American Academy of Pediatrics' policy statement on breastfeeding and the use of human milk, "Extensive research, especially in recent years, documents diverse and compelling advantages to infants, mothers, families, and society from breastfeeding and the use of human milk for infant feeding. These include health, nutritional, immunologic, developmental, psychological, social, economic, and environmental benefits.

Benefits for the mother Breastfeeding has also been shown to be beneficial to the mother. The act of breastfeeding releases hormones which have been found to both relax the mother and cause her to experience nurturing feelings toward her infant. Breastfeeding as soon as possible after giving birth increases levels of oxytocin which encourages a more rapid contraction of the uterus and in turn decreases postpartum bleeding. Breastfeeding can also allow the mother to return to her pre-pregnant weight as the fat stores accumulated during pregnancy are utilised in milk production. Frequent and exclusive breastfeeding delays the return of menstruation and fertility (known as lactational amenorrhoea) allowing for improved iron stores and the possibility of natural child spacing. Breastfeeding mothers experience improved bone re-mineralisation postpartum, and a reduced risk for both ovarian and pre/post-menopausal breast cancer.