Estrogen, the female sex hormone, varies in terms of normal levels. When tested, estrogen levels are measured based on picograms per milliliter, abbreviated as pg/ml. What doctors consider as normal estrogen levels for a woman of reproductive age and normal levels of a post-menopausal woman vary. Likewise, estrogen levels fluctuate based on where a woman is in her menstrual cycle. Typically, the amount of estradiol, the predominant form of estrogen in human females, ranges between 50-400 pg/ml for women of reproductive age and under 20 pg/ml for menopausal and post-menopausal women.
The female body actually produces three different types of estrogen: estrone, estradiol, and estriol. Estradiol is responsible for signaling the body to begin the ovulation process, as well as other stages of the menstrual cycle. As one of three forms of estrogen, estradiol is the most prominent. Testing estrogen levels most often equates to testing for estradiol.
In women of typical reproductive age, the level of estradiol in the body fluctuates from day to day, even from hour to hour. The body releases hormones in short pulses, based on numerous physiological factors such as stages of the menstrual cycle, environmental and dietary factors, and age. If a woman’s body releases a pulse of hormones just before a testing series, the results would naturally show higher levels, although not necessarily high enough to classify as abnormally elevated levels. Since so many factors influence the amount of estrogen in a woman’s system at any given time, the span of test results deemed within normal range is understandably wide.
For menopausal women, normal estrogen levels typically do not fluctuate as much as during reproductive years. Since a woman’s menstrual cycle ceases after menopause, the body requires less estradiol. The body no longer needs to rely on hormones circulating in the body to trigger the ovulation cycle, so estrogen levels obviously drop in response. The hormonal system needs only to produce enough estrogen to maintain essential body functions, resulting in more stabilized, predictable estrogen levels.
Consistently lower-than-normal estrogen levels in women of typical reproductive age can signal fertility issues and other health problems. For example, low levels of estrogen occur in anorexic women, athletes undergoing extreme training routines, women with polycystic ovarian syndrome, as well as women with a recent failed pregnancy. Alternatively, elevated levels of estrogen can signal different health problems, such as ovarian or adrenal tumors, diabetes, obesity, and high blood pressure. Medications such as steroids and ampicillin also affect normal estrogen levels.