Estrogen, the dominant female hormone, fluctuates at different times during your life and at different times during the menstrual cycle. Men produce estrogen, too, although not in the same amounts that women do. If estrogen levels vary from the normal range, you may experience fertility problems. The ovaries in women produce estrogen; men produce estrogen from male hormones, called androgens. The dominant form of estrogen and the level most frequently measured is called estradiol.
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If you're a woman of reproductive age, your estrogen level falls to its lowest level in the first few days of the menstrual cycle. Estradiol levels at the beginning of the menstrual cycle normally fall to between 20 and 40 picograms per milliliter, or pg/ml. As an egg-containing follicle in the ovary begins to mature, estradiol levels rise to between 150 to 280 pg/ml or more. Estradiol levels rise after ovulation until the start of the next menstrual period, when they fall to 50 to 100 pg/ml unless pregnancy occurs.
During pregnancy, estradiol levels, along with progesterone and human chorionic gonadotopin, or hCG, remain elevated and continue to rise significantly throughout pregnancy. A study presented at the American College of Rheumatology/Association of Rheumatology Health Professionals, (ACR/ARHP,) Annual Scientific 2009 meeting on the correlation between lupus symptoms and estrogen tested mean estradiol levels during pregnancy. During the first trimester, the mean was 726 pg/ml with a range of 139 to 1,389. In the last trimester, levels ranged from 906 to 9,385 with a mean of 5,056 pg/ml. Urine and serum pregnancy tests measure hCG, not estrogen.
Menopausal women normally have very low estradiol levels, less than 10 pg/ml. During perimenopause, the several years before menopause occurs, estradiol levels fluctuate considerably and often are higher than normal on day 2 or 3 of the menstrual cycle. Estradiol levels over 80 pg/ml may indicate decreased ovarian reserve in perimenopause. When ovarian reserve decreases, you may have more difficulty getting pregnant, according to reproductive endocrinologist Bruce Rose, M.D.
Estrogen levels in men generally fall into the same range as those of postmenopausal women, or between 10 and 50 pg/ml. Unlike women, whose estrogen levels drop with age, men generally experience a rise in estrogen levels as they get older, along with a drop in testosterone, the dominant male hormone. Estrogen dominance in men contributes to breast growth and prostatic hypertrophy. An increase in estrogen levels is also a major cause of prostate cancer, John Lee, M.D., author and pioneer in hormone replacement therapy, explains.