Causes of Menopause
Menopause begins naturally when your ovaries start making less estrogen and progesterone, the hormones that regulate menstruation. The process gets under way in your late 30s. By that time, fewer potential eggs are ripening in your ovaries each month, and ovulation is less predictable. Also, the post-ovulation surge in progesterone — the hormone that prepares your body for pregnancy — becomes less dramatic. Your fertility declines, perhaps partially due to these hormonal effects.
These changes are more pronounced in your 40s, as are changes in your menstrual pattern. Your periods may become longer or shorter, heavier or lighter, and more or less frequent. Eventually, your ovaries shut down and you have no more periods. It's possible, but very unusual, to menstruate every month right up to your last period. You're much more likely, though, to have a gradual tapering off.
Unfortunately, there's no way to know exactly which period will be your last. You have to wait until well after the fact — 12 months after, by official definition. In your final months before reaching menopause, it's still possible to get pregnant, but it's quite unlikely.
Because this process takes place over years, menopause is commonly divided into the following two stages:
- Perimenopause. This is the time you begin experiencing menopausal signs and symptoms, even though you still menstruate. Your hormone levels rise and fall unevenly, and you may have hot flashes and other symptoms. Perimenopause may last four to five years or longer.
- Postmenopause. Once 12 months have passed since your last period, you've reached menopause. Your ovaries produce much less estrogen and no progesterone, and they don't release eggs. The years that follow are called postmenopause.
