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Try it free today! In females, the reproductive period, or fertility
period refers to the years of monthly menstrual cycles between the first menstrual period,
which happens at puberty and then the permanent stopping of menstrual cycles – which is called
menopause. Menopause usually sets in around age 50, and it’s preceded by a couple of
years of hormonal and physical changes and this is called perimenopause. To be more specific,
a woman’s entered menopause when an entire year has passed since her last menstrual period. During the reproductive period, the ovaries
have basically got a ton of ovarian follicles scattered inside them. And each ovarian follicle
is made up of a ring of granulosa and theca cells surrounding a primary oocyte the core.
And during each menstrual cycle, one of these follicles ruptures at ovulation, and it releases
the oocyte out into the fallopian tube – where it can be fertilized by a sperm, or it can
just carry on down its path and you don’t get pregnant. So the weird thing is, even
though females are born with millions of follicles, only about 400 of them are actually mature
enough to release their oocyte throughout the lifetime. So, if you’re ever feeling
useless just think of those ones that have gone to waste, eh? Anyway, all of this process is ultimately
controlled by the hypothalamus, which is all the way away from the gonads up in the brain.
And the hypothalamus secretes gonadotropin releasing hormone, or GnRH, which travels
to the nearby pituitary gland and makes it secrete two hormones of its own – follicle-stimulating
hormone, or FSH, and luteinizing hormone, or LH. FSH and LH then make the ovarian follicles
secrete sex hormones. So, the theca cells make androstenedione, a sex hormone precursor
that the granulosa cells convert into estradiol – a member of the estrogen family – and progesterone.
The menstrual cycle on average lasts about 28 days, and for the first two weeks, which
are called the follicular phase, the granulosa cells make more estrogen sends a negative
feedback signal to the pituitary which inhibits the production of FSH; likewise, progesterone
inhibits LH production during the second half of the menstrual cycle – so hormone levels
are constantly regulated, and this leads to a cyclic and predictable pattern in hormone
secretion during the reproductive period. During each menstrual cycle, a couple of follicles
are stimulated by FSH and LH, until one of them emerges as the dominant follicle and
ruptures at ovulation, and the rest of them , well, it’s pretty bleak really, they just
degenerate off and die. Over time, many ovarian follicles degenerate, and the ones that remain
become less and less sensitive to FSH and LH. This goes on until menopause, when there
are no remaining follicles responding to gonadotropins, and that causes the menstrual cycles to cease
entirely. Now, a couple of years before menopause, the
woman enters a transition period called perimenopause. And during perimenopause, the ovaries have
a lot less functional follicles, so the menstrual cycles preceding menopause are often anovulatory.
Anovulatory means, without ovulation, and that’s because none of the follicles are
responsive enough to FSH and LH stimulation in order to mature and release the oocyte
at ovulation. The lack of ovulation can cause missed or irregular periods, and they become
more irregular and more infrequent as the ovarian follicle start to run out even more.
And fewer follicles also means less estrogen and progesterone, so less inhibition on the
hypothalamus and the pituitary. And in turn, the hypothalamus and pituitary produce more
frequent, larger bursts of GnRH, FSH and LH – the difference is, though, the pattern of
secretion is much more erratic than during the reproductive period, this erraticness,
along with decreasing estrogen levels can cause a bunch of problems and these include
hot flashes and night sweats which can lead to trouble sleeping, and also vaginal dryness,
which can lead to dyspareunia which is pain during sex. Also, estrogen normally has a
protective effect on both the cardiovascular system where it helps to keep the blood vessels’
walls nice and flexible to accommodate blood flow, as well as the skeleton, where it helps
sustain bone density. So, low levels of estrogen can also lead to complications like cardiovascular
disease and osteoporosis. So women entering menopause should have their LDL cholesterol
levels checked, and, if high, dietary changes or medical therapy with statins may be required.
Osteoporosis is diagnosed using a dual-energy x-ray absorptiometry, or a DXA, test – and
screening should start at 65 in the general female population, and 60 in smokers. This
test measures bone mineral density at different sites throughout the body, like the lower
spine and hips, and results come back as a T score and a Z score. A Z score lower than
2.5 standard deviations at any site confirms osteoporosis. Finally, changes in hormone
levels can also impact the mood, so women going through menopause may experience irritability
or mood swings. So, even though transitioning into menopause
is a natural step in the aging of the female reproductive system, these symptoms may have
a negative impact on overall well-being. The good news though, is that the body can adjust
to the hormone changes, so they actually go away on their own after a couple of years.
But in the meantime, there are tons of ways that we alleviate them. For hot flashes and
night sweats it’s really useful to avoid “triggers” like hot drinks and spicy foods,
as well as, just, maintaining a cool ambient temperature. Additionally, selective serotonin
reuptake inhibitors like venlafaxine can help with both hot flashes and psychological symptoms
like mood swings and irritability. In some cases, hormone replacement therapy with estrogen
can also be used to relieve hot flashes – however, all women with an intact uterus need a progestin
in addition to estrogen to prevent endometrial hyperplasia and cancer. Women who have undergone
hysterectomy should not receive a progestin, because it’s key benefit is prevention of
endometrial hyperplasia and carcinoma, and that’s no longer relevant. For vaginal dryness,
there are things like vaginal estrogen creams and lubricants that can be during sex to help
with pain. And in attempt to prevent osteoporosis, calcium and vitamin D supplements can be used.
If osteoporosis is diagnosed, medical therapy with bisphosphonates should be initiated.
OK, so let’s wrap up the key points: menopause refers to the natural halting of the monthly
menstrual cycles and this is because of the depletion of ovarian follicles. It’s usually
considered that a woman has entered menopause when more than 1 year has passed since her
last menstrual period. This usually happens around the age of 50, and it’s preceded
by a couple of years of hormonal changes may manifest as hot flashes and night sweats,
as well as mood changes. Avoiding certain foods and maintaining a cool ambient temperature,
using vaginal creams and lubricants, as well as certain medications, can help manage the
symptoms of menopause.


  1. once more, diet can make a huge difference. I never had any premenopause symptoms just because i learned how milk is deleterious to human health and i had already qut milk. over 20 years ago, there was no milk in Chinese population, and women did not experience any pre-menopause syndrome. And other countries alike!

  2. My mom is goin through the transition phase and it sucks (im assuming). This cleared a lot up n stuff. Thanks

  3. Venlafaxine is not approved by the FDA for hot flashes and techincally it is not an SSRI. There is an actual SSRI, paroxetine, which is approved by the FDA for hot flashes.

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