Lecture 21: Menopause Flashcards
Describe the evolution of menopause
Females experience relatively early onset of reproductive system failure compared to other organs
What are the four theories of why menopause occurs;
1) Blessings of modern life
2) Senescence
3) Group Selection
4) Good mother/grandmother theory
Describe the theory of senescence;
- To protect the woman from hazards of child birth
- Deterioration of reproductive processes as woman age
Describe the theory of group selection;
menopause protects against birth defects causes by age related deterioration of follicle quality (follicles metabolically active, so older they become, the crappier they are)
Describe the good mother / grand mother theory;
A pause from reproduction to provide external maternal care of offspring
Evidence suggests improved outcomes for children with grandparents present
What is menopause;
The last natural menstrual bleed (represents end of womans reproductive life)
When does menopause typically occur?
50-52
Why does menopause occur?
Atresia and ovulation result in exhaustion of follicular reserve
Remember, 30 follicles a day enter growth cycle and only 30 are selected for further growth with one becoming dominant
What is POF;
Ovarian failure under age of 40 years
What is the popcorn hypothesis?
Quality and quantity of follicles decline with age
Describe factors that influence timing of menopause;
Smoking
Poor nourishment
age of menarche
maternal age of menopause
All may influence the age of menopause
race doesnt
What does smoking do?
Increases the rate of follicle loss
Describe the phases of menopause;
Pre-menopause (normal cycles) 40-46 Menopausal transition (46-menopause_ Menopause (last bleed) Post menopause Ovarian sénescence Perimenopause
What is perimenopause;
The time from menopausal transition to ovarian senescence
What is ovarian senescence?
Absolute end of fertility in ovaries
What is a sign that a female may be in the perimenopausal stage?
Menstrual cycle becomes longer (76% 4+ days)
Therefore less likely to be ovulatory
What are older women more likely to have?
They are more likely to be anovular (15%)
Give a brief overview of perimenopausal changes;
Menopausal transition -> Ovarian senescence
- Erratic hormone fluctuations
- Climacteric (physical and emotional symptoms)
- 5-10% dont experience these transitional symptoms
Describe the first sign of perimenopause;
- Follicle level drops below critical threshold (25k)
- Inhibin B levels decline (release by granulosa cells) (part of n. feedback) thus
= Increased FSH - Acceleration of follicle loss
= Shortened follicular phase
= Increased early follicular estrogen
Describe what does changing FSH lead to?
Higher FSH levels during the last decade of reproductive life leads to greater portion of primordial follicles entering the growing pool thus acceleration of follicle depletion.
Describe the features of perimenopause;
- Accelerated depletion of follicular reserve
- Irregular cycles
- Anovular
- unpredictable hormone patterns
- contraception is difficult
Describe chaning hormone levels during menopause;
Decrease inhibin B
= FSH (10-20x) and LH (4-5x) increase
Oestrogen decrease (80-90%) Androgen decrease (15%)
Can menopause be diagnosed?
No endocrine tests can be done, is retrospective diagnosis
What may indicate menopause
45+ who has been anovular for 12 months (98% change of menopause)
