Breast feeding Lactation is an important physiological event of puerperium.

The primary function of breast feeding is to provide nutrition for the new baby

The secondary functions are:Protection against infant infections & various diseases.Inhibition of ovarian activity.Encouragement of uterine involution.

Physiology of lactation The breast development occur during puberty

mainly& each breast compose of 20 lobules arranged radialy from the nipple. Each lobule compose of glandular tissue & ductal system which is branching & then unite to form a single duct which open on the nipple.

The glandular tissue compose of alveoli. The duct & the alveoli are surrounded by myoepithelial contractile cells.

During pregnancy there is hypertrophy of the alveoli & ductal system of the breast. This hypertrophy is due to the effect of estrogen , progesteron ,prolactin, growth hormone & adrenal steroid.

Milk production Secretion of milk & colostrum begin in the 2nd

trimester but it is minimal due to the inhibitory effect of estrogen.

Establishment of lactation include 2 similar but independent mechanisms:

The release of prolactin which acts upon the glandular cells of the breast to stimulate milk secretion.

The releases of oxytocin which acts upon the myoepithelial cells to induce milk ejection reflex.

The release of both hormones is stimulated by an afferent neorological stimuli from the nipple( which become very sensitive to tactile stimuli immediately after delivery) to the hypothalamus.

Milk secreation Prolactin is a long chain polypeptide released from

the lactotrophs in the anterior pituitary stimulated by the nipple stimulation during suckling.

Its level is dependent on the strength, frequency & duration of suckling stimuli

Its peak level is reached after 30-45 minutes after suckling & return to basal level after 2 hours.

Prolactin secretion is under the neuro-endocrine control of a prolactin inhibitory factors from hypothalamus which is dopamine ,so its secretion is inhibited by dopamine agonist which is bromocriptine.

Prolactin will act on the secretary cells of the breast to stimulate the synthesis of milk proteins (casein, lactoglobulin& lacalbumin) , lactose & lipids.

Milk ejection reflex This reflex Is mediated by the release of

oxytocin from the posterior pituitary & it will stimulate contraction of the myoepithelial cells which ware situated round the milk secreting glands & wall of the ducts longitudinally. So the contractions of these smooth muscle will

cause: Expelling of milk from the gland. Dilatation of the ducts & encouraging free flow

of the milk. Oxytocin secretion is stimulated by tactile

stimulation of the areola by suckling & also by sensory input such as the mother seeing or hearing her baby crying, while prolactin is stimulated by tactile stimulation of the areola.

Oxytocin have a very short halve life in the circulation & released from the pituitary in a pulsatile manner.

The milk ejection reflex may be inhibited by

emotional stress.

Composition of colostrum & breast milk From the 1st 2 days after delivery colostrum is secreted & on the 3rd & 4th days the secretion is changed to normal breast milk.

Colostrum is a yellow fluid containing large fat globules & has a high mineral, moderate proteins & relatively low sugar content

It has a high content of Ab spatially secretary Ig A which has an important role against infections

When the secretion changes from colostrum to milk ,its color changes to bluish white .

Advantage of breast feeding1. Breast milk is a natural food for the human infant.2. Inexpensive3. Always at appropriate temp.4. Protect against infections.5. Contribute to the development of infant – mother

attachment.6. Protection against diseases as juvenile DM ,

inflammatory diseases or atopic illnesses as asthma or eczema.

7. Improved neurological development.8. Breast feeding decrease the incidence of breast

cancer in premenopausal women .9. Suppression of ovarian activity.

Problems during breast feedingIt may be related to the infant or the mother

Causes related to the infant Disease of the infant such as pneomonia or other inf. Disproportion between the size of the nipple & the baby’s

mouth but this can be remedied as the baby grows. Cleft lip & cleft palate or micrognethia . Nasal obstruction

Causes related to the mother Retracted nipple. Cracked or sore nipple which is mainly due to incorrect

fixation of the baby (which may be due to breast engorgement caused by infrequent feeding )or due to fungal skin infection

Treatment is:

1. Encourage frequent feeding &if the breast is so tens & engorged allow manual milk expression or expression by pump.

2. Educate the mother about correct positio & fixation of the baby to the breast.

3. Lubricate the nipple by the terminal milk drops which are rich in fatty material.

4. Treatment of fungal infection if present.

Breast engorgement that usually occur on the 3rd or

4th day after delivery & the breast become painful, tender ,swollen , red & shiny. This is usually relieved by frequent feeding

Drugs during lactation Drugs should be avoided during lactation unless

there is definite clinical indication because some of the drug or its degradation product is likely to be secreted

in the milk..

Secretion of drugs in the milk depend on its molecular wt. ,size, its binding protein , solubility in water or lipid.

The effect of the drug depend on whether it appear in the milk in its active or inactive metabolite, the rout of administration , the drug half life.

Other factor to be determined is whether the infant gut can absorb the drug or the drug can be detoxified or

excreted .

Some steps can be taken to minimize the potential effect of maternal medication on the infant as:

1. The long acting form of the drug should be avoided

2. The drug is given immediately after feeding so the peak level in maternal blood will subside by the next fed

3. The infant should be watched carefully for possible adverse effect such as change in feeding habits , sleeping pattern if the mother taking anti epileptic drugs, skin rash or other unusual signs as bleeding tendency in infant of a mother taking anticoagulant drugs.

Protection against infections1. The breast milk contain lactoferrin which bind to iron &

because E.coli require iron for growth ,multiplication of the organism is inhibited

2. Breast feeding encourage the colonization of the gut by a non pathogenic flora which will competitively inhibit pathogenic strains.

3. Breast milk contain a bactericidal enzymes as lysozymes.

4. Ig A which is a secretary Ig secreted by the lymphoid tissue of the gut (Peyer’s patches) & transferred to the breast milk & is not absorbed from the infant gut but remain to attach to specific pathogen.

5. Breast milk contain a living cells as polymorphs ,lymphocytes & plasma cells which may be active against invading pathogens.

Suppression of ovarian function This secondary function of lactation which is called

lactational amenorrhea is caused by a suckling induced effect or change in the hypothalamus sensitivity to the feedback effect of ovarian steroid

During lactation the hypothalamus becomes more sensitive to the negative feedback effect & less sensitive to the positive feedback effect of estrogen

This mean when the pituitary secret enough FSH & LH to initiate follicular development ,the consequent estrogen secretion will inhibit G n release & follicle will fail to mature.

during the 1st 6 moths of life the failure rate of exclusive breast feeding as contraceptive is 1-2% but increase to 10% after 6 months.