Natural or Surgically-Induced Menopause

Frederick R. Jelovsek MD, MS

"Have there been any studies comparing a "natural" menopause to a surgically-induced menopause? Has there been any medical consensus that one is more advantageous for a woman's health? I am 51 and still having regular menstrual periods. Thanks!" S.Z.

There is very little data about this topic mainly because there are rarely pure groups of women who have been studied who have either:

• natural menopause with no hormone replacement therapy (HRT with estrogen and progestin)
• natural menopause with HRT and long term continuous use (10 years or more to get the heart disease, osteoporosis, Alzheimer's disease and colon cancer prevention benefits)
• surgical menopause (ovary removal prior to natural cessation of menses) who do not take any estrogen replacement therapy (ERT)
• surgical menopause who take ERT for long term continuous use

There are studies of some of these groups of women but they are mostly for 1-3 years. About two thirds of women will discontinue ERT or HRT even after they have had substantial benefits from it, due to fear of breast cancer. Thus it can be very difficult to tell about how the basic process of natural menopause and surgical menopause differ. There is indirect evidence in the literature that we can use to discuss some of the questions below.

The way your question is asked and the fact that you are still not undergoing menopause at age 51 makes me think you may be contemplating surgical removal of the ovaries at the time of another procedure. Please excuse me if I am reading too much into your question but the next question and its answer does play a role in the overall topic of surgical versus natural menopause.

Surgery And Menopause

If I am not yet menopausal but I'm going to have major pelvic surgery, should I have the ovaries removed producing a surgical menopause, or have the doctor leave them in in order to wait for a natural menopause?

The main discussion point about taking or leaving in normal ovaries at the time of other surgery such as a hysterectomy, revolves around the amount of benefit and length of time the ovaries would secrete beneficial hormones such as estradiol and testosterone and their benefits over taking hormone replacement versus the long term risk of developing ovarian cancer at a future date if the ovaries are left in. Most estradiol (estrogen) production from the ovary stops at the time of menopause and testosterone secretion goes significantly down and then to zero from the ovary within about two years of menopause. After this there is felt to be absolutely no benefit as far as hormone production from the ovaries. Testosterone itself does not go down to zero because it is manufactured in the fat cells from adrenal hormones. In fact it stays fairly constant after natural menopause.

The lifetime incidence of a woman developing ovarian cancer is about 1.8%. This is over all ages however, and the older you become, the higher the chance that you will get ovarian cancer; in fact at age 85 there may be as high as a 17% chance of ovarian cancer. The rate goes up to about 2.3% if there is a family history of colon or breast cancer. The rate is lower than 1.5% if a woman has used oral contraceptives for 5 years or more. Women of African American descent will have about a 20% lower incidence of ovarian cancer compared to Caucasian women.

Therefore, removing the ovaries at the time of hysterectomy can prevent a certain number of instances of ovarian cancer but that varies depending upon a woman's background and past history. Across the board, the reduction in the overall percent of ovarian cancer cases is:
Ovary removal during hysterectomy -

• at age 40 - 11% reduction
• at age 45 - 7% reduction
• at age 50 - 4% reduction (but up to 16% reduction if all abdominal surgeries are considered.)

Thus "prophylactic" ovary removal at the time of other surgery can reduce ovarian cancer.

Future cancer risk must be weighed against losing the ovarian hormones earlier than one would lose their function naturally. You would think that a woman could just take ERT but many women cannot or will not take ERT and for each year earlier they are without ERT, their overall death rate goes up from excess heart disease, hip fracture and colon cancer which is not offset from less breast cancer. When estrogen replacement compliance is considered it is generally better to leave the ovaries in at the time of hysterectomy especially if a woman is more than 5 years away from a spontaneous menopause. The general rule of thumb for many doctors is to remove ovaries at the time of hysterectomy if a woman is over age 45 and to leave normal ovaries if a woman is under age 40. Between 40-45 there is not widespread agreement and decisions might best be made upon family history and likelihood of ERT compliance.

Are the symptoms of menopause more severe or last longer with surgical menopause or natural menopause?

Women who are retrospectively asked about their menopausal symptom severity and duration years after undergoing menopause and who had surgical menopause will have a more positive view of their energy level, sexual libido and general well-being than women undergoing natural menopause. This may be because of the relief they obtained from the surgical problem they were having that led to the hysterectomy and ovarian removal, a higher incidence of having been replaced with estrogens without having to take progestins or just simply a different perception, but it argues against surgical menopause producing worse symptoms than natural menopause. It is almost impossible to separate effects since about 85-90% of women undergoing surgical menopause receive estrogen replacement versus about 50% of women with a natural menopause in some studies.

It seems clinically that there is a much higher incidence of hot flashes with surgical menopause than with natural menopause although how high the incidence is may vary by a woman's ethnic background. If given estrogen replacement right away, however, the hot flashes seem to be controlled.

Psychological symptoms of menopause have some conflicting evidence in the literature. In general it is not felt that menopause causes specific psychological conditions, eg. depression, anxiety, separate from the physical symptoms with perhaps the exception of decreased cognitive function. With surgical menopause, there is not a negative psychological outcome if estrogen is not replaced, although the good cholesterol, HDL, falls significantly. Keep in mind that the physical symptoms of menopause such as hot flashes, night sweats and sleep disturbances will produce secondary psychological symptoms in women (the "brain fog" described on many menopause bulletin boards). Also, women who have underlying psychological conditions may worsen with the acute drop of estrogens at menopause but the lack of estrogens do not cause the new occurrence of such conditions.

Menopause Treatments And Surgery

Are the long term benefits of HRT or ERT any different in women who have undergone surgical versus spontaneous menopause?

With regard to osteoporosis, the rate of bone loss right after surgical menopause is higher than it is for natural menopause. Presumably this is because women with natural menopause have already lost a fair amount of bone mineral density already. We know that women who underwent surgical menopause and take ERT will prevent the usual loss of bone density that takes place in a natural menopause and that women undergoing natural menopause who take HRT will replace most of the previously lost bone mass.

With a surgical menopause, estrogen replacement needs to be at higher levels, eg., conjugated estrogens 1.25 mg or estradiol 2 mg, than it does for later in a natural or surgical menopause in which a woman's body has already become used to lower levels. This is also true to prevent bone loss. A dose of .625 mg conjugated estrogens may not be enough to prevent bone loss in the first year after menopause, whereas a higher dose, or a 0.625 mg dose combined with a phytoestrogen dose of ipriflavone from red clover such as found in Promensil ®, can prevent that initial menopausal high rate of bone loss.

Other than osteoporosis, we really do not know for sure about any differences between natural and surgical menopause on the effect of heart disease prevention, colon cancer prevention, Alzheimer's disease prevention, prevention of blindness from acute macular degeneration or a slight rise in the incidence of a well-differentiated breast cancer. Every condition seems to be dependent upon whether a woman is able to take estrogen replacement rather than whether the menopause was surgical or natural.

How do hormones change over time in natural menopause versus surgical menopause?

Studies that measure the longitudinal changes of hormone levels over time tell us that hormone levels start changing several years before menopause and stabilize about 2 years after menopause. The following graphs illustrate how estrogen (estradiol) and testosterone change in natural menopause and with surgical menopause.

As you can see, the main difference between natural and surgical menopause is the rapid rate of drop of both estradiol and testosterone that occurs with removal of the ovaries. This occurs almost over night at the time of the surgery. Testosterone gradually goes back up over time because of peripheral conversion of other adrenal hormones, but if there is any time that a woman needs testosterone supplements, it would be at the time of ovary removal if she is not yet menopausal.

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