Physiology of lactation in obstetrics and gynecological nursing

1. SHRI SHANKARAACHAARY COLLEGE
OF NURSING, HUDCO, BHILAI
Subject- Obstetrics and Gynaecological Nursing
SEMINAR
ON
Physiology of Lactation
Guided By
Submitted By
Mrs. Saumya Thomas Ms.
Monika Kosre
Assistant Professor (OBG) Msc.
Nursing 1st year

3. Introduction
■ The normal physiology of lactation is a
process that begins to take effect well
before the initial latch of the newborn
infant. It require the breast to change in
composition, size and shape during each
stage of female development.

4. Definition
According to DC Dutta
Lactation describes the secretion of milk from the
mammary glands and the period of time that a
mother lactates to feed her young.
According to Nima Bhaskar
Lactation, secretion and yielding of milk by females
after giving birth. The milk is produced by the
mammary gland, which are contained within the
breast and the process of lactation is physiology of

5. Lactation
■ Lactation is under the control of
numerous exocrine glands, particularly
the pituitary hormone prolactin and
oxytocin.
■ It is influenced by the sucking process
and by maternal emotions.
■ Lactation, the process of breasts feeding
results from the interplay of hormones,
instinctive reflexes and learned behavior
of the mother and newborn.

6. Factors to determine establishment
and maintenance of lactation
■ The anatomical structure of mammary gland
and development of alveoli, ducts and nipples.
■ The initiation and maintenance of milk
secretion
■ The milk ejection or propulsion of milk from the
alveoli to the nipples.

7. Stages of lactation
■ 1. Preparation of breasts (mammogenesis).
■ 2. Synthesis and secretion from the breast alveoli
(lactogenesis).
■ 3. Ejection of milk (galactokinesis).
■ 4. Maintenance of lactation (galactopoiesis).

8. Preparation of breast
(Mammogenesis)
■ Pregnancy is associated with a
remarkable growth of both the ductal
and lobuloalveolar systems. An intact
nerve supply is not essential for growth
of the mammary glands during
pregnancy.

9. Synthesis and secretion from the
breast alveoli (Lactogenesis)
■ Milk secretion actually starts on 3rd or 4th postpartum
day. Around this time, the breasts become engorged,
tense, tender and feel warmth. When the progesterone
and estrogen are withdrawn following delivery,
prolactin begins its milk secretory activity.
■ The secretory activity is enhanced directly or indirectly
by growth hormone, thyroxine, glucocorticoids and
insulin. Prolactin stimulates mammary glandular ductal
growth and epithelial cell proliferation and induces milk
protein synthesis.

10. Stages of lactogenesis
Stage 1:
■ Occurs by mid pregnancy.
■ Mammary gland becomes competent to secrete milk.
■ Lactose, total protein, and immunoglobulin concentrations increase within the secreted
glandular fluid, whereas sodium and chloride concentrations decrease.
■ High circulating levels of progesterone and estrogen hold the secretion of milk in check.
Stage 2 (day 2 or 3 to day 8 after birth):
■ Occurs around the time of delivery.
■ Onset of copious milk secretion.
■ Blood flow, oxygen, and glucose uptake increase, and citrate concentration increases
sharply.

11. Ejection of Milk ( Galactokinesis)
■ Discharge of milk from the mammary glands depends not only on the suction
exerted by the baby during suckling but also on the contractile mechanism
which expresses the milk from the alveoli into the ducts.
■ During suckling, a conditioned reflex is set up: Ascending impulses from the
nipple and areola thoracic sensory (4, 5 and 6) afferent neural arc
paraventricular and supra optic nuclei of the hypothalamus Oxytocin from the
posterior pituitary produces contraction of the myoepithelial cells of the alveoli
and the ducts containing milk. ("milk ejection" or "milk let down" reflex) Milk is
forced down into the ampulla of lactiferous ducts, wherefrom it can be
expressed by the mother or sucked by The baby.
■ Presence of the infant or the infant's cry can induce letdown without suckling.
A sensation of rise of pressure in the breasts by milk experienced by the mother
at the beginning of the sucking is called "draught". The milk ejection reflex is
inhibited by factors such as pain, breast engorgement or adverse psychic
condition

13. Maintenance of lactation
(Galactopoiesis)
■ Prolactin appears to be the single most important
galactopoietic hormone. Continuous suckling is essential
for removal of milk from glands, also release prolactin.
Secretion is the continuous process unless suppressed by
congestion or emotional disturbances.
■ Milk production - A healthy mother will produce about 500-
800 ml of milk/day with about 500 Kcal /day. This
requires 600 Kcal/day for the mother which must be made
up from the mother’s diet or from her body store. For this
purpose a store of about 5 kg of fat during pregnancy is
essential to make up any nutritional deficit during
lactation

14. Lactogenesis (milk initiation)
■ It begins during the later part of pregnancy. Colostrum
is secreted as a result of stimulation of the mammary
alveolar cells by placental lactogen, a prolactin like
substance. It continues after birth as an automatic
process. The continued secretion of milk is related to-
1. Sufficient production of pituitary hormone prolactin
2. Maternal nutrition

15. Colostrum
■ A yellow, pre-milk substance, high in protein and
contains antibodies. It’s production decreases gradually
after childbirth and production of true milk begins.
■ The bluish white true milk usually comes in between 3rd
and 5th postpartum day.
■ The milk at the beginning of the feeding is known as
fore milk which contains less fat and flows at a faster
rate than at the end of the feeding.
■ The hind milk Is white and contains more fat, calories
and is believed to satisfy the infant and signal that the
feeding should come to an end.

16. The last stage
■ The last stage of human lactation is ingestion of milk by
suckling baby. The full term healthy new born baby
possess three instinctive reflexes needed for successful
breast feeding:-
1. The rooting reflex
2. The sucking reflex
3. The swallowing reflex

17. Inadequate milk production
■ It may be due to infrequent suckling
or due to endogenous suppression of
prolactin (ergot preparation,
pyridoxin, diuretics or retained
placental bits). Unrestricted feeding
at short interval (2-3hrs.) is helpful.

18. Drugs
■ Metoclopramide (10 mg thrice daily) increases milk
volume (60-100%) by increasing prolactin levels.
■ Sulpuride (dopamine antagonist) has also been found
effective.
■ Intranasal oxytocin contracts myoepithelial cells and
causes milk let down reflex.

19. Lactation suppression
■ Bromocriptine (dopamine agonist that inhibits prolactin) 2.5 mg, 1 tab
daily for 10-14 days.
■ Side effects are: hypotension, rebound breast engorgement,
secretion, myocardial infarction and puerperal stroke.
■ Suppression of lactation is necessary if the baby is born dead or dies
in the neonatal period or if breast feeding is contradicted.