From the time menses begins until menopause, levels of estrogen and progesterone ebb and flow in a manner which promotes reproduction. At about age 35 to 40, women reach the time of premenopause, which is when their levels of progesterone and estrogen begin to reduce.
Normal Hormone Progression
During this time through age 50, there is a 35% drop in estrogen, but a 75% reduction in progesterone occurring simultaneously. This is normal, and does create many premenopausal symptoms that we accept as part of the aging process.
Many women in their mid-thirties, most women during premenopause, and even many women during menopause are overloaded with estrogen. At the same time they are suffering from progesterone deficiency because of the severe drop in physiological production during this period. There is then insufficient progesterone to counteract the amount of estrogen in our body. It is most noticeable among peri-menopausal women who do not ovulate, which is quite common. You may have a fairly normal cycle, but no egg is released and very little progesterone is produced.
It is not the absolute deficiency of estrogen or progesterone, but rather the relative dominance of estrogen and possible deficiency of progesterone that is main cause of health problems when they are not in balance. The end result: excessive estrogen relative to progesterone, add up to a condition Dr. John Lee has termed “estrogen dominance.” Dr. Lee’s books, What Your Doctor May NOT Tell You About Premenopause and What Your Doctor May NOT Tell You About Menopause explain this and more in-depth.