Estrogen dominance is a term popularized by Dr. R. Lee – a Harvard trained medical doctor-in the early 90s. From his research, he reached the conclusion that perimenopausal and menopausal symptoms arise as a result of progesterone deficiency. He revolutionized the concept of using estrogen and progesterone for hormone replacement therapy and particularly for treating symptoms associated with menopause.
As you approach menopause, your hormone balance becomes drastically altered. There is low estrogen in the luteal phase (second half of the menstrual cycle) because the quality of the eggs gradually diminishes. You also ovulate less often.
Progesterone is produced by the corpus luteum (what is left after the egg is released from the ovary). In the absence of ovulation,there is no corpus luteum and therefore no progesterone.
In contrast, estrogen levels drop to about 40-60% of pre-menopausal levels, leading to an imbalance between the levels of estrogen and progesterone.
Shortly after menopause, there are no eggs left in the ovaries so progesterone and estrogen are no longer produced there. However, estrogen is still being produced from the conversion of the hormones testosterone and androstenedione (androgens) in other parts of the body e.g. fat cells.
Factors that affect the degree of estrogen dominance
The levels of estrogen vary from one menopausal woman to another depending on various factors.
- Body weight – the more you weigh, the more estrogen you will have. This is because fat converts androgens into estrogen. This also explains the increased tendency of obese women to develop cancer of the uterus (womb)which is stimulated by high estrogen levels relative to progesterone (i.e. unbalanced estrogen).
- Levels of binding proteins – Most of the estrogen in your body is attached to special proteins and circulates in the blood in this form. The amount of free estrogen is thus very small and this is the one that produces its effects. At midlife the levels of these special proteins tend to lessen, leaving more free estrogen in the blood.
- Levels of androgen – After menopause and with increasing age, the adrenal glands produce less androgens, which means less formation of estrogen.
- Stress – Prolonged stress leads to increased production of androgens by the adrenal glands which are converted to estrogen and can lead to estrogen “excess” and estrogen dominance symptoms.
- Exposure to environmental toxins – Substances like car exhaust fumes, pesticides, hormones in meat and some soaps contain xenoestrogens that act like estrogen in the body.