Hi. Now we’re gonna talk about menopause management.
What’s the difference between menopause and the perimenopause?
Are they really that different? Well, let’s see.
Menopause is the permanent cessation of menses
due to decreases in ovarian estrogen production.
This is evidenced by 12 consecutive months of no menstrual bleeding.
So it’s usually a retroactive diagnosis versus the perimenopause
or the climacteric which is the transitional period which can occur from 2 to 8 years
from reproductive to nonreproductive stage. This is marked by a menstrual irregularity.
Let’s review how the perimenopause works. In another lecture we reviewed oogenesis.
Oogenesis begins at 4 weeks and the peak oogenesis occurs mid gestation
and then we lose follicles through atresia after that time through birth, puberty,
and all the way to the menopause. At birth, we have 1 to 2 million oocytes
in our ovarian reserve. By puberty we have about half a million
and by the age 30 to 35 when you’re advanced maternal age
you have a hundred thousand. By the time we get to menopause,
we have less than a thousand.
Let’s talk about the hormones that are actually increased.
So we know that follicle-stimulating hormone or FSH
increases during the menopausal period.
We also see a corresponding decrease in estradiol production.
So mechanisms that increase FSH are follicular atresia leading to decreased ovulation,
decreased estradiol, and that increases FSH.
The remaining aging follicles exhibit diminished capacity to secrete inhibin B.
This also leads to increased FSH. Premenopausal FSH level
should be less than 10 ideally. Sometimes in the perimenopause
we can already start to see an elevation in the FSH
and by postmenopause we see that the FSH is greater than 30.
In the perimenopause be careful, women can still become pregnant
and in fact they’re more likely to ovulate twice and have twins.
Let’s now talk about estrogens. Estrogen levels do not gradually wane,
but remain stable and at sometimes they are slightly elevated due to the high FSH.
Let’s talk about the different types of estrogens.
We have E2 or estradiol and estrone. Estradiol seems to be the only one
to decrease less than a year before menopause so when premenopausal women
usually we make about 30-200pg/ml.
In the postmenopause, we have much less at 25-30pg/ml.
We’re gonna talk about how that feels for a woman
after being exposed to estrogen her entire reproductive life
and then losing estrogen. Then we’re gonna talk about estrone.
This is an extragonadal estrogen as it’s usually made peripherally
but can also be made in the ovary. This is the primary estrogen
in the menopausal woman and the premenopausal levels
are between 35-500pg/ml and the postmenopausal range it’s 10-15pg/ml.
So how does this work? The hypothalamus usually gives input
through FSH to the ovary. Typically, FSH works upon the ovary
to make steroidogenesis actually occur with the addition of luteinizing hormone.
Aromatase converts androgens to estrogens and the estrogens feedback
to the pituitary and the hypothalamus.
This happens when we are in our normal reproductive phase.
Aromatase in the postmenopausal woman
actually causes peripheral estrogen production, primarily estrone,
which also feeds back to the hypothalamus and pituitary.
Let’s now discuss the endocrine profile in the perimenopause.
I don’t want you to think that you need to check hormone profiles on women
to determine if they’re in their perimenopause or menopause.
Remember that menopause is a clinical retroactive or retrospective diagnosis
that you can only make after the patient has 12 consecutive months
with no menstrual bleeding. However, I do wanna call your attention
to the fact that there are some hormones that start to decrease or increase
in the perimenopause. One such hormone is anti-mullerian hormone
and it starts to decrease to undetectable levels,
5 years before the final menstrual period and the decreasing AMH
actually corresponds to an increase chance of twinning.
Therefore, women in their perimenopause need adequate contraception.
Let’s now review inhibin B. Inhibin B starts to decrease in women
who are 35 years of age and older.
Remember that 35 years of age in obstetrics is advance maternal age.
Finally, luteinizing hormone, because of the decrease in inhibitory factors
LH is increased during the menopause.
Lastly, testosterone decreases by about 25%
due to adrenal cortex hypoplasia and the loss of cyclical LH surges.