Stages of Lactation PDF

Preview

Summary

Stages of Lactation...

Description

STAGES OF LACTATION There are 4 stages of lactation 1) MAMMOGENESIS (growth and development of the mammary gland)

Gestation - Breast development starts at 5 weeks of fetal life along the mammary ridge or milk line - Maternal hormones (from placenta) cause lobules and alveoli to develop - Colostrum can be present in newborn at birth = witch’s milk Infancy - Male and female breasts are the same in infancy and before puberty Puberty - During each menstrual cycle: a) Estrogen causes further arborization (branching at the end of nerve fibre) of ducts b) Progesterone causes proliferation of glandular tissue - Arborization is increased during pregnancy & lactation – the shape of breast changes as it matures Mature - Breasts are usually fully developed by age 20 - Further growth during each follicular and ovulatory phase, then regression - Until age 30, the changes in each cycle are advantageous, as post-menstrual cycle regression is not complete

Pregnancy - Two phases occur during pregnancy: a) Mammogenesis – rapid development of glandular tissue and ducts, darkening of areolar pigments b) Lactogenesis I – or lactation, onset of milk secretion begins due to breast changes during pregnancy and continues until full milk production occurs in the first few days postpartum. Lactating (Lactogenesis II) - Full secretory activity of alveolar cells and milk production

2. LACTOGENESIS

Lactogenesis I - Prolactin causes alveolar structures to change into milk-producing cells - Colostrum is secreted by second trimester – first milk that baby receives - Progesterone inhibits milk production - After birth, the placenta leaves (major source of progesterone) - This initiates milk production (lactogenesis II) - This happens regardless whether mom breastfeeds or not, due to hormonal shift

The infant’s gut at birth is completely permeable

-

Colostrum is thick like latex paint and decreases the permeability of the gut. This prevents passage of large particles and pathogens Growth factors in colostrum cause gut to mature Every effort should be made not to give formula to breastfed infants before gut closure occurs

Lactogenesis II - Occurs 2-3 days postpartum - Onset of copious milk production - Mothers feel this stage as the “milk coming in” = Hormonal Control - If infant fails to begin suck and remove milk from breast, the secretion of milk will decline

3. GALACTOPOIESIS -

Maintaining the milk production (Lactogenesis Stage III) Milk composition changes so that by day 10, it is called “mature milk” This process is under = Autocrine Control (dependent on infant suckling – milk removal)

4. INVOLUTION -

Termination of milk production – takes about 40 days after the last feeding The experience of mother and composition of milk will be different if the process is abrupt or gradual Sodium, chloride, protein, lactose levels outside of typical norms = suggest weaning or mastitis...