If you are a woman reaching a certain age, you might be wondering about the menopause. For example, when does the menopause start and is it the same for every woman?
The answer, as with everything about the human body, is not simple. There are average ages for the onset of the menopause, normally between 44 and 55 years. But it can vary immensely between women. Some women start the menopause in their early thirties, whereas others don’t have symptoms until they are fifty. So why does the menopause start in the first place?
Why does the menopause start at all?
The menopause is the natural end to a woman’s reproductive cycle. The menopause starts when a woman has no more eggs left. At birth, females have around 1 to 3 million eggs available. However, this number has dramatically reduced to about 400,000 by the time a girl has her first ever period.
A very small number of eggs are lost through ovulation. Women will release between 400 to 500 eggs in their lifetime through ovulation. But, the vast majority are lost through something called atresia. Eggs are housed within a protective ovarian follicle.
This protective environment has everything the egg needs to mature and survive. However, from the moment of birth, these follicles begin to decline. So, by the time a girl has reached puberty she has only a few hundred thousand follicles with eggs inside left.
Atresia is a natural process and doesn’t result in a menstrual bleed. During menstruation about 15 – 20 follicles prepare themselves to release an egg. The follicle that responds the most to a stimulating hormone (follicle stimulating hormone or FSH) will go on to produce an egg.
Over time the quality of the follicles and the eggs they are housing starts to decline. As we age, these remaining eggs become resistant to FSH and as a result, the body stops producing estrogen. This is the beginning of the menopause for most women. The period before full menopause is called the ‘perimenopause’.
Why does the menopause start at different times for women?
So, the average age for the menopause to start is about 51 years. But there are many other reasons why it can begin earlier.
Premature Menopause
If the menopause starts before the age of 40 it is called premature menopause. There are different causes of premature menopause.
Primary Ovarian Insufficiency (POI)
Primary ovarian insufficiency or premature ovarian failure is when a woman’s ovaries stop working before the age of 40. POI affects around 1% of US women and women who have a sister or mother with the condition are more likely to develop it themselves.
The exact cause of POI is not known. However, experts believe the problem lies with the follicles.
- Follicle dysfunction: There are enough follicles in a woman’s ovaries but they do not function normally.
- Follicle depletion: There are not enough follicles in a woman’s ovaries and she runs out earlier than expected.
Medical Menopause
Surgery
A hysterectomy is the surgical removal of the uterus. It does not necessarily mean that a woman will immediately enter the menopause if she has her uterus removed. It all depends on whether her ovaries are removed also.
Once the ovaries are removed then a woman will enter the menopause immediately. This is because there are no more eggs to release. Some women do experience menopausal symptoms after a hysterectomy as the blood supply to the ovaries has been disturbed.
Chemotherapy
During chemotherapy, some women may have irregular or no periods at all. Some chemotherapy medicines can also cause damage to the ovaries. Usually, once the chemotherapy has stopped the symptoms of the menopause disappear.
This is because the ovaries recover. However, it all depends on the age prior to treatment and the type of treatment used.
Ethnicity
Your ethnicity can have a slight effect on the time you enter the menopause. For example, the average age for a Caucasian woman to reach the menopause is about 51. However, African-American and Hispanic women start the menopause a bit earlier.
Not only that but for Chinese and Japanese women it can be a bit later.
Smoking
Nothing damages healthy tissue like smoking. And a woman’s ovaries are no different or any less susceptible to this damage. Therefore, if you smoke it is likely that you’ll reach the menopause earlier than if you don’t.
So, several factors affect the start of the menopause. But can we predict when our own menopause will begin? Well, there are clues that can help us. But there is one overwhelming factor that will dictate the start of a woman’s menopause. And that is when her mother entered hers.
“Menopause is strongly genetically linked, so you’re very likely to fall within a few years either way of the age your mother was at menopause.” Nanette Santoro, MD, board member of the board of directors of the American Society for Reproductive Medicine.
Factors that do not influence when the menopause starts are birth control methods, the age of puberty or how many pregnancies a woman has.
So, it is not possible to predict when the menopause starts, but experts say that women over the age of 45 should start watching out for symptoms.
“If you’re over the age of 45 and skip at least three periods in a row, that tells us that you’re going to move on to menopause relatively soon,” Santoro says. “But we’re still working on blood tests to see if we can predict this more accurately.”
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By Janey D.
