What is menopause?
The permanent cessation of ovulation and menstruation, resulting from ovarian failure (loss of ovarian follicular activity).
Between 46-55 years (average age of 51)
Diagnosed after a year of amenorrhea with high FSH levels
What is early menopause?
Natural menopause occurring between 40-45 years.
What is premature menopause or ovarian insufficiency (POI)?
Ovarian failure or insufficiency before age 40.
Primary = chromosomal, genetic, autoimmune.
Secondary = pelvic radiation therapy, chemotherapy, bilateral oopherectomy, hysterectomy.
D/t increase risk for CVD and bone loss, HRT recommended until at least age 51.
What are the events in perimenopause?
- Accelerated decrease in ovarian follicle number (ovarian reserve) - starts 10-15 years before menopause
- initial maintenance or increase in estradiol levels
- changes in menstrual cycle
- decreased progesterone secretion
- final decrease in follicle number and estrogen production.
How are follicular reserves decreased in perimenopause?
Decrease release of inhibin and AMH which inhibit FSH. Results in increase FSH and increase follicular recruitment causing a depletion.
Why are estradiol levels elevated during perimenopause?
Increase in FSH due to decrease in inhibin and AMH.
FSH increases aromatase activity in granulosa cells converting androgens to estradiol.
What is the role of elevated estrogen during perimenopause?
Causes an earlier LH surge thus earlier ovulation and a shortened follicular phase of the menstrual cycle.
What is late perimenopause
Occurs 1-3 years before FMP (final menstrual period).
- more dramatic changes
What happens to progesterone in perimenopause?
Progesterone was produced by the corpus luteum but with early ovulation you have an underdeveloped lutem and a decline in progesterone production.
Describe the end stage of perimenopause:
- high FSH (but no effect on ovaries)
- high LH (maintains androgen synthesis by ovaries)
- sharp decrease in estrogen d/t follicular depletion
- ovarian progesterone synthesis stops after the FMP
What happens to estrogen post menopause?
Androgens (androstenedione and testosterone) are produced by the adrenal glands and the ovarian stromal cells.
Androgens are converted mainly to estrone (and some estradiol) in adipose cells)
Estrone (a weak estrogen) is the dominant estrogen postmenopause
