Breast Physiology and Benign Diseases 3

Question 1

What happens to breast physiology during the menstrual cycle and at menses?

Answer 1

• —During menstrual cycle
  
  • estrogen peaks just prior to mid-cycle
    
    • —causes enlargement of the breast ducts
  • progesterone peaks around day 21 during the luteal phase
    
    • —causes growth of the breast lobules
  • increased fluid secretion, mitotic activity and DNA production of both non-glandular and glandular tissue occurs and may cause breast tenderness
  • volume of a premenstrual breast increases by 25-30 ml due to increased blood flow and water retention
• —At menses:
  
  • —Normalization of hormone levels causes breast size to return to normal and tenderness to resolve

Question 2

What happens to breast physiology during pregnancy?

Answer 2

• —Prolactin levels increase through the course of pregnancy
  
  • —10-25ng/ml to 200-400 ng/ml at term
• —Estrogen, progesterone and prolactin cause new duct formation, ductal branching, and alveolar proliferation
  
  • —This along with placental lactogen likely cause breast size increase in pregnancy
  • —Breast tenderness is also common and likely due to high levels of progesterone in pregnancy

Question 3

Describe breast physiology during lactation due to effects of the major hormones that regulate the breast during this time.

Answer 3

• —Prolactin:
  
  • —Produced by the anterior pituitary
  • —Stimulates milk production within the alveolar cells of the breast
• —Oxytocin:
  
  • —Produced by the posterior pituitary
  • —Stimulates myoepithelial cells surrounding the alveoli that lead to milk ejection into milk ducts
  • —“Milk ejection reflex”
• —Progesterone and Estrogen
  
  • —Are both at high levels during pregnancy
  • —Inhibit lactation by interfering with prolactin binding of the alveolar cells
  • —Drops with delivery of the baby and placenta lead to lactation due to the longer presence of prolactin in the body

Question 4

Describe the physiology of lactation pertaining to triggering of secretion and milk production.

Answer 4

• —Milk secretion begins at 3-4 days postpartum
  
  • due to decrease in circulating steroid hormones
• —Suckling causes
  
  • —increase in prolactin levels
    
    • —initiation and maintenance of milk production
  • increase in oxytocin levels
    
    • afferent arc: due to stimulation of the paraventricular and supraoptic nucleus of the hypothalamus which produce oxytocin and signal the posterior pituitary gland
    • —efferent arc: occurs with release of oxytocin and stimulation of breast myoepithelial cells to milk let down
• —Thyroid hormone, Insulin, Insulin-like GF, Cortisol all necessary for optimal breast milk development
• —Initially, colostrum is produced
  
  • high levels of WBCs and IgA which coat the baby’s intestines and help prevent pathogens from invading and decrease food allergy

Question 5

What are the top five benefits of breast feeding?

Answer 5

• Decreased otitis media (50%)
• Decreased respiratory infections (72%)
• Decreased GI infections (64%)
• Decreased NEC (58%)
• Decreased SIDS (36%)

Question 6

Describe the proces of lactation cessation.

Answer 6

• Occurs with decreased suckling and decreased milk letdown
• Lack of suckling also leads to reactivation of dopamine production
  
  • negatively feeds back and decreases prolactin production
• Dopamine agonists have been used historically to aid in stopping breastfeeding but are no longer recommended due to significant side effects

Question 7

What are benefits of breastfeeding for the mother?

Answer 7

• —Decreased postpartum blood loss due to uterine involution
• —Increased child spacing
• —Decreased rate of postpartum depression
• —Decreased premenopausal breast cancer and ovarian cancer
• —Decreased rate of type 2 DM in women who did not have GDM
• —Possible increase in return to pre-pregnancy weight
• —AAP recommends exclusive breastfeeding for 6 months with continuation of breastfeeding for 1 year or longer

Question 8

What are the contraindications of breast feeding?

Answer 8

• —True CIs
  
  • infants born with classic galactosemia
  • —in the US, mothers with HIV
• —Relative CIs
  
  • untreated active TB, active HSV lesions on the breast, active varicella, and H1N1 should be separated from infants but may be given expressed milk
• —Misconceptions:
  
  • —Hepatitis B
  • —Hepatitis C
  • —CMV
  • —Substance abuse and smoking

Question 9

What are the contraceptive effects of breast feeding?

Answer 9

• —Elevated prolactin levels inhibit pulsatile secretion of GnRH from the hypothalamus
• Therefore, decreases levels of FSH and LH and inhibits estrogen production and ovulation
• —Lactational Amenorrhea Method:
  
  • —breast feeding at regular intervals
    
    • < 4 hrs during the day
    • < 6 hrs at night
  • exclusive breastfeeding means supplemental feedings can not exceed 5-10 % of total feedings
  • breast pumping may decrease the the neuroendocrine response and may increase likelihood of ovulation/pregnancy
  • after 6 months or with menstruation, this contraceptive method is less effective

Question 10

What is the effect of contraception post-partum on breast feeding? When should it be started? And what are some good contraceptive choices?

Answer 10

• —Should take into consideration, patient’s plan for breastfeeding
  
  • exclusively breastfeeding: begin contraception 6weeks- 6 months PP
  • partial breastfeeding/no breastfeeding: initiate contraception between 3 and 6 weeks
• —Contraceptive choices:
  
  • —non-hormonal methods will not interfere with breastfeeding
  • —progestin methods: begin at 6 weeks PP
    
    • —Pills, Mirena IUD, Depo-Provera
  • combination hormonal methods:
    
    • debated whether effects milk production