Breast Physiology and Benign Diseases 3 Flashcards
What happens to breast physiology during the menstrual cycle and at menses?
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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
- estrogen peaks just prior to mid-cycle
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At menses:
- Normalization of hormone levels causes breast size to return to normal and tenderness to resolve
What happens to breast physiology during pregnancy?
- 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
Describe breast physiology during lactation due to effects of the major hormones that regulate the breast during this time.
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Prolactin:
- Produced by the anterior pituitary
- Stimulates milk production within the alveolar cells of the breast
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Oxytocin:
- Produced by the posterior pituitary
- Stimulates myoepithelial cells surrounding the alveoli that lead to milk ejection into milk ducts
- “Milk ejection reflex”
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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
Describe the physiology of lactation pertaining to triggering of secretion and milk production.
- Milk secretion begins at 3-4 days postpartum
- due to decrease in circulating steroid hormones
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Suckling causes
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increase in prolactin levels
- initiation and maintenance of milk production
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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
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increase in prolactin levels
- 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
What are the top five benefits of breast feeding?
- Decreased otitis media (50%)
- Decreased respiratory infections (72%)
- Decreased GI infections (64%)
- Decreased NEC (58%)
- Decreased SIDS (36%)
Describe the proces of lactation cessation.
- 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
What are benefits of breastfeeding for the mother?
- 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
What are the contraindications of breast feeding?
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True CIs
- infants born with classic galactosemia
- in the US, mothers with HIV
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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
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Misconceptions:
- Hepatitis B
- Hepatitis C
- CMV
- Substance abuse and smoking
What are the contraceptive effects of breast feeding?
- Elevated prolactin levels inhibit pulsatile secretion of GnRH from the hypothalamus
- Therefore, decreases levels of FSH and LH and inhibits estrogen production and ovulation
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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
- breast feeding at regular intervals
What is the effect of contraception post-partum on breast feeding? When should it be started? And what are some good contraceptive choices?
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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
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Contraceptive choices:
- non-hormonal methods will not interfere with breastfeeding
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progestin methods: begin at 6 weeks PP
- Pills, Mirena IUD, Depo-Provera
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combination hormonal methods:
- debated whether effects milk production