Physiology of Lactation in Obstetrics and gynecological nursing seminar Msc nursing

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 1 st year

2. 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 .

3. 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 lactation.

4. 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.

5. 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 .

6. 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). 

7. 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.

8. Synthesis and secretion from the breast alveoli (Lactogenesis) Milk secretion actually starts on 3 rd or 4 th 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 When the progesterone and estrogen are withdrawn following delivery, prolactin begins its milk secretory activity.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.

9. 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.

10. 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

11. 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

12. 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- Sufficient production of pituitary hormone prolactin Maternal nutrition

13. 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 3 rd and 5 th 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.

14. 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:- The rooting reflex The sucking reflex The swallowing reflex

15. 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 .

16. 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.

17. 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.