Mammogenesis
Growth and development of the breast
Lactogenesis
Functional changes to allow for milk secretion
Galactopiesis
Maintaining milk production
Involution
Termination of milk production
The 4 hormones involved in Mammogenesis
Visible changes to the breast during pregnancy
The breast enlarges due to alveolar lobule formation, subcutaneous veins also enlarge. The areolar darkens and the Montgomery glands produce lipoid fluid to moisturise the nipple.
2 stages of Lactogenesis
Galactopoiesis
Milk production is initially dependent on Prolactin. From 9 days following birth, production of milk is under autocrine control, continued milk production depends on regular milk removal. There is continuous secretion of milk in the alveoli, if the milk isn’t removed there is accumulation of the feedback inhibitor of lactation and an increase in intramammary pressure. The feedback inhibitor regulates the amount of milk produced so its dependent on the infants needs. When the milk is removed the inhibitor is removed.
Galactokinesis- milk ejection
Oxytocin stimulates milk ejection. When the infant suckles the nipple the touch sensitive mechanoreceptors are stimulated in the nipple. The sends nerve signals via the intercostal nerves to the dorsal root ganglion and then to the Hypothalamus. Oxytocin is made from Hypothalamic paraventricular cells and is secreted from the posterior pituitary gland into the blood stream and causes contraction of myoepithelial cells in the mammary glands. Pushes milk down the lactiferous duct and out through the nipple.
Cause of onvolution in the breast tissue
Alveolar cells shrink and loose their secretory function due to an accumulation of inhibitory peptides. Occurs when the feedback loop described above stops and the baby stops suckling. Normally starts 40 days after last breastfeeding. Epithelial cells no longer require their secretory function so are removed by apoptosis and required by adipocytes.
Variety in breast milk
The longer the intervals between feeds, the lower that fat content. The longer the baby suckles, the more fat and less lactose sugar in the feed. The fact content peaks mid-morning and is lowest overnight.
Composition of Colostrum
Primary role may be immunological not nutritional. It contains higher amounts of white blood cells and antibodies, especially IgA which coats the lining of the infants immature intestine. High concentration Protein, growth factors, antimicrobial products and electrolytes. There are low concentrations in fat and carbohydrate
Difference in mature breast milk
Produced in large volumes and predominantly nutritional role. High concentrations of carbohydrates (especially lactose), fat. Low concentration of proteins, growth factors, antimicrobial products, electrolytes. The composition of breast milk is dynamic and varies with feeding and over the lactation period
Composition of breast milk
Breastfeeding benefits
Difference in composition between breast milk a
1) Breast milk has low concentrations of vitamin D.
2) There is less efficient absorption of the components of formula milk.
3) Formular milk might not provide the right type of macronutrients and lacks in variety, in fats formula milk lacks DHA, cholesterol and lipase.
Problems with breast feeding
* Too much milk being produced
What makes a bad latch
A poor latch could be due to Cleft lip/palate or Tongue tie (Ankyloglossia) where there is unusually short/thick lingual frenulum. Sore or cracked nipples can be caused by a poor latch, this can cause a fistula
Candidal infection
Thrush of the nipples. Overgrowth of Candida albicans within the nipple and duct. Its caused by sore or cracked nipples and recent antibiotic use
Presentation of Candidal infections- nipple
Complications of having too much milk
Breast engorgement -> Blocked milk ducts -> Mastitis -> Abscess
Breast engorgement
When the breast becomes swollen, hard, tight and painful. Usually affects both breasts. Occurs in the first few days of breastfeeding when milk is not removed adequately, this could be due to delayed initiation of breastfeeding, poor latching or ineffective suckling. Pressure within the breasts can damage the cell
Management- improve removal of milk
Mastitis
Inflammation of the breast, usually occurs 2-3 weeks following birth. Due to milk stasis, which causes inflammation which can develop infection. Most infective cases are due to organisms from the infant’s nasopharyngeal or umbilical area – staphylococci or streptococci, normally Staphylococcus aureus. Caused by incomplete emptying of the breast and prolonged gaps between feeds.
Presentation of Mastitis