Topics to be covered

What is lactationAnatomy of the breastDevelopment of the breastHistology of the lactating mammary glandHormonal control of Breast growth and lactationComposition of milk

What is lactation?Feeding human breast-milk to provide for the nutritional needs of infantsAn alternative to human breast milk is by using formula feeding which is food products designed to provide for the nutritional needs of infants. They include powders, concentrates or ready-to-use forms

Milk Formula•Should contain the right balance of nutrients according to the age of the infant or child and formulated as close as possible to breast milk i.e.,

nutrient contents automatically changes with babies’ needs

•DHA (Docosahexaenoic Acid), Protein, Sialic acid, choline, taurine, other omega 3 and 6, inulin dietary fibr, calcium, iron, essential vitamins and vital minerals in quantities appropriate for infants and children developmental needs. •Some also contains L Bifidus, a type of friendly and beneficial bacteria found in the intestinal tract which enables the child to obtain all the goodness from food for growth & development.

•Available in either regular, honey, mild chocolate or fine cereals  •Some powders which are soya based are formulated for lactose intolerance babies. Soya based milk is quite expensive.

Examples of milk formula/powder in Malaysia

Breast milk is the best!!!!

Milk glands

AreolaProper latching on

Anatomy of breast

External structure External structure Breast situated on the anterior chest Breast situated on the anterior chest

wall between 2wall between 2ndnd and 6 and 6thth ribs, ribs, extended to the sternum and axillaextended to the sternum and axilla

In the centre-erectile structure-nippleIn the centre-erectile structure-nipple Has 15-29 opening of lactiferous Has 15-29 opening of lactiferous

duct.duct. The areola is area of loose skin with The areola is area of loose skin with

18-20 sebaceous gland.18-20 sebaceous gland.

AnatomyInternal structureInternal structure Mature breast consist of glandular tissue, ductalMature breast consist of glandular tissue, ductal

tissue, fibrous tissue and fatty tissuetissue, fibrous tissue and fatty tissue

A. Glandular tissueA. Glandular tissue Produce milkProduce milk Acinar secretory cell are arranged to Acinar secretory cell are arranged to

alveolusalveolus Alveolus will form lobulesAlveolus will form lobules Lobules will form lobesLobules will form lobes There are 15-20 lobes, each consist of 20-There are 15-20 lobes, each consist of 20-

40 lobules which include 10-100 alveoli40 lobules which include 10-100 alveoli

B. Ductal tissueB. Ductal tissue Transport milkTransport milk

Group of alveoli empty their milk into Group of alveoli empty their milk into distal lactiferous ductdistal lactiferous duct

Many lactiferous duct units to form Many lactiferous duct units to form major duct.major duct.

Each major duct widen to form an Each major duct widen to form an ampulla (lactiferous sinus) as it reach ampulla (lactiferous sinus) as it reach the areolathe areola

Each ampulla narrow to formEach ampulla narrow to form separateseparate opening on the nippleopening on the nipple

C. Fibrous tissueC. Fibrous tissue Support the breastSupport the breast

Chest wall superficial fascia condenses Chest wall superficial fascia condenses to form multiple fascial bands ( Cooper to form multiple fascial bands ( Cooper ligaments)ligaments)

D. Fatty tissue D. Fatty tissue comprises of 85% of breastcomprises of 85% of breast Responsible for bulk and shapeResponsible for bulk and shape

Picture 1: Breast structure

Formation of mammary glands During birth, mammary glands consists

of sparse alveoli and abundant lactiferous ducts

After puberty, under the influence of estrogen, these ducts will produce branches which ends in polyhedral granular cells that are dense, small and circular (true alveoli)

E and P4 will stimulate the growth of ductal-lobular-alveolar system and breast enlargement with fat deposition and growth of connective tissue

Breast changes during pregnancy

Breast hypertrophy occur with Breast hypertrophy occur with pregnancypregnancy

Size increase 400g eachSize increase 400g each Blood flow doubleBlood flow double Areola enlarged and pigmentedAreola enlarged and pigmented Montogomery glands becomes Montogomery glands becomes

prominent.prominent. Increase fat deposition and retention Increase fat deposition and retention

of fluid and electrolyteof fluid and electrolyte

Hormonal control of breast and lactation

Breast growth during pregnancy is Breast growth during pregnancy is associated with increase levels of associated with increase levels of oestrogen, progesterone, hPL and oestrogen, progesterone, hPL and prolactin from maternal pituitaryprolactin from maternal pituitary

Oestrogen promote duct growthOestrogen promote duct growth However alveolar development require However alveolar development require

full complex of hormonesfull complex of hormones Oestrogen and progesterone inhibit Oestrogen and progesterone inhibit

lactogenic effects of hPL and prolactinlactogenic effects of hPL and prolactin After delivery, rapidly decreasing level After delivery, rapidly decreasing level

of steroidsof steroidsmilk secretion occurmilk secretion occur

Histology of lactating breastHistology of lactating breast Alveolar epithelium consists of short columnar cells with

microvillous surface There is a prominent endoplasmic reticulum and golgi

apparatus at the base of cells Both fat droplet and vesicle(lactose&protein) from GA

fuse with the cell membrane and discharged into lumen. Milk are stored alveoli, duct and cistern When lactation ceases extensive degeneration of

lactogenic cells, a phagocytic reaction and fatty tissue infiltration

Milk ejection reflex

Suckling stimulates release of Suckling stimulates release of prolactin and oxytocin via prolactin and oxytocin via neurological pathways between neurological pathways between nipple and the hypothalamus.nipple and the hypothalamus.

Milk ejection is brought about by the Milk ejection is brought about by the contraction of myometrial cells contraction of myometrial cells around the alveoli and ducts under around the alveoli and ducts under influence of pituitary oxytocin.influence of pituitary oxytocin.

This sharp increase in prolactin This sharp increase in prolactin secretion,secretion,

diminishes progressively over 3 months diminishes progressively over 3 months of BFof BF

No direct relationship between prolactin No direct relationship between prolactin level and milk yieldlevel and milk yield

The most important factors are removal The most important factors are removal of the milkof the milkpromotes further milk promotes further milk productionproduction

In the absence of suckling, maternal In the absence of suckling, maternal level of prolactin reduced slowly to level of prolactin reduced slowly to reach non pregnant value after 2-3 reach non pregnant value after 2-3 weeksweeks

Milk ejection reflex

MER – a neuroendocrine reflex and a conditioned reflex

Apart from touch and pressure on the nipple, stimulation from a baby’s cry for milk, thoughts of your baby and lactation times can cause milk let-down

This conditioned reflex is more for release of oxytocin and not prolactin

Stimulation to vagina and cervix can also cause milk let-down

MER can be inhibited due to pain after labour, anxiety and worries whether you are feeding the baby enough

All these will cause inhibition of oxytocin release

Fertility during lactation

Some women assumes their menstrual cycle right after puerperium

Some women may have no menses for almost a year or as long as baby is breast-feeding (Prolactin inhibits the hormones for control of regular menstruation)

May be use as a natural contraceptive

Advantages of breast milk Free Comes at the right temperature Release on demand Changes to suit baby’s needs Comes in an attractive package

Stage of lactation(Summary)

Stages Stages Defination Defination OnsetOnset Initiating Initiating eventsevents

Ostrogen, Ostrogen, progesteroprogesterone, ne, prolactinprolactin

MammogenesMammogenesisis

Preparing Preparing breast for breast for milk milk secretionsecretion

Puberty Puberty Increasing Increasing level of level of oestrogen oestrogen and and progesteroneprogesterone

Oestrogen Oestrogen

ProgesteroneProgesterone

Prolactin, GH, Prolactin, GH, insulin, insulin, cortisolscortisols

Lactogenesis Lactogenesis Initiation of Initiation of milk milk secretion in secretion in alveolialveoli

Post Post partumpartum

Declining O, Declining O, P, hPLP, hPL

prolactinprolactin

GalactopoiesiGalactopoiesis s

Maintanace Maintanace of of established established milk milk secretionsecretion

After After each each emptying emptying of duct of duct and and alveolialveoli

Periodic Periodic suckling suckling

Oxytocin Oxytocin prolactinprolactin

Colostrum Colostrum

Is a yellow fluid containing fat laden cells and large quantity of protein and minerals.

Secreted first 24 – 48 hours of life Highest absorption occurs in first 24 hours of life Contains relatively higher levels of IgG, IgM, and

IgA including antibodies to bacteria esp E.coli After 1st week, predominant IG is secretory IgA

Composition of human milk (produced 2 to 3 days post delivery)

Component Component HumanHuman

WaterWater 85%85%

Carbohydrate Carbohydrate 7% (Lactose)7% (Lactose)

ProteinProtein 1-1.5% (40% casein)1-1.5% (40% casein)

LipidsLipids 3.5% (palmitic, oleic acid)3.5% (palmitic, oleic acid)

EnzymesEnzymes Amylase, catalase, peroxidase, lipase to Amylase, catalase, peroxidase, lipase to help in digestionhelp in digestion

MineralMineral Vit A abundantVit A abundant

Immunology Immunology IgA protect against enteric bacteria, T and IgA protect against enteric bacteria, T and B cell lymphocytes provides active B cell lymphocytes provides active immunityimmunity

When lactation stops, the involution of the mammary glands occur after three months

Distension and mechanical atrophy occurs to the epithelial

structure, rupture to the alveoli wall and formation of cavities in the mammary tissue

Alveolar distension will cause alveolar hypoxia After phagocytosis of dead cells, the lobular-acinar

structure becomes smaller and the ductular system predominates

The alveolar lumen decreases and dissapears and the surface changes to a double non-secretory layer

Milk production can also be terminated by a lactation depressant using bromocriptine, an agonist receptor Dopamine D2 that inhibits prolactin release

Other Breast milk benefit