S8) The Post-natal Period

Question 1

Provide 3 definitions of the post-natal period

Answer 1

• Period from the delivery of the placenta to 6/52 post natal
• Period when the pregnancy changes revert to the pre-pregnancy state
• Period of great changes/modifications in lifestyle, psychology, activities, relationships, responsibility, etc.

Question 2

Describe the hormonal control of growth and development of mammary tissues

Answer 2

• Progesterone, oestrogen, prolactin, GH and adrenal steroids cause hypertrophy in pre-existing alveolar-lobular structures in the breast
• There is also formation of new alveolae by budding from the milk ducts, with proliferation of milk-collecting ducts

Question 3

There are high levels of lactogenic hormones (prolactin and hPL) in pregnancy.

Why are only minimal amounts of milk are formed?

Answer 3

Oestrogen and progesterone inhibit the effects of lactogenic hormones

Question 4

How is prolactin released in the post-natal period?

Answer 4

Prolactin is released by the action of suckling at a nipple that has become exquisitely sensitive post-delivery

Question 5

What is the determining factor for milk production?

Answer 5

Prolactin levels and milk production are dependent on the frequency and duration of suckling

Question 6

When are prolactin levels at their highest?

Answer 6

Prolactin levels are at their highest in the early puerperium and reduce slowly, only returning to normal after weaning

Question 7

Identify another determining factor for milk secretion

Answer 7

• Milk secretion is also dependent on adequate emptying of the secreting glands
• Accumulation of milk inside the alveoli will cause distension and atrophy of the glandular epithelium

Question 8

In 4 steps, describe the hormonal control of the let down reflex

Answer 8

⇒ Oxytocin stimulates myoepithelial cells around the alveolae

⇒ These cells contract and expel the milk into the milk-collecting ducts

⇒ The longitudinal muscle cells in the ducts are stimulated

⇒ These cells dilate to improve the free flow of milk towards the nipple

Question 9

Describe the neuroendocrine mechanism controlling the production of milk

Answer 9

Question 10

Describe the neuroendocrine mechanism controlling the secretion of milk

Answer 10

Question 11

What effect does stress have on oxytocin release?

Answer 11

• Maternal stress reduces oxytocin release
• Increased levels of adrenaline & noradrenaline reduces mammary blood flow, oxytocin release from pituitary and myoepithelial cell contractile response to oxytocin

Question 12

Describe the anatomical position of the breast

Answer 12

• Breast is located on the anterior thoracic wall and extends horizontally from the lateral border of the sternum to the mid-axillary line
• It spans between the 2nd and 6th intercostal cartilages and lies superficially to the pectoralis major and serratus anterior muscles

Question 13

Describe the topography of the breast

Answer 13

Question 14

What is the most prominent gland in the breast?

Answer 14

Sebaceous gland