Welcome to the rest of your life! Menopause, according to the doctors, is that six months to one year after you have your last period. This time of life is defined by exactly what the word means: the cessation of your monthly flow. But that's not the whole story.
The physical and emotional changes caused by menopause — and the dramatic change in the hormones circulating in your body and connecting to receptors from your brain to the bend in your big toe — will continue for the rest of your life.
It starts out innocently enough. During perimenopause, which can begin as early as age 38 and continue until menopause, you get a hint or two of what's coming. Your periods may become irregular, and even vary between shorter and scantier or longer and heavier flows. You may have a few hot flashes, or night sweats, completely soaking your pajamas and sheets.
The ability of your hypothalamus (a wedge-shaped tiny gland deep in the brain) to naturally and easily regulate body temperature seems to falter. Since that gland also triggers your thyroid's secretion of the hormones that regulate metabolism, you could watch yourself gain weight without even varying from your diet or exercise regimen by one iota. And you might feel extremely tired from time to time.
What's happening is that your ovaries are beginning to feel the effects of age. Not only do you not have as many eggs as you had before, but the follicles that contain them don't work as efficiently as they once did.
Even if an egg matures, it may not actually be expelled from that follicle, leaving you with cysts and an incomplete cycle. Since you ovulate less frequently, that cuts back on your production of the hormones estrogen, progesterone and androgen (testosterone).
But frequently what's not happening in perimenopause is the luteal phase of the cycle when the egg moves from the sac to the fallopian tube and down into the uterus to be fertilized. It's this phase that gives you the right amount of the hormone progesterone, which usually balances your fluctuating levels of estrogen.
While all this is going on in your pelvis, the hypothalamus and pituitary glands in your brain are simply refusing to believe it. They send out signals of increasing intensity, in the form of follicle stimulating hormone (FSH) and luteinizing hormone (LH), to tell your ovaries what to do.