Estrone, or E1, is a type of estrogen hormone that plays a role in various bodily functions. It is one of three primary estrogens, alongside estradiol (E2) and estriol (E3). Healthcare providers frequently measure estrone levels through a blood test to gain insights into an individual’s hormonal balance. This article explains estrone, the reasons for testing its levels, how to interpret the results, and the practical aspects of undergoing an estrone blood test.
What Estrone Is
Estrone (E1) is a naturally occurring steroid hormone. While less potent than estradiol, estrone becomes the predominant estrogen after menopause, when ovarian function declines. The body produces estrone primarily in the adrenal glands and fatty tissues (adipose tissue), with some production also occurring in the ovaries.
Estrone also functions as a reservoir for estrogen, meaning the body can convert it into more active forms, such as estradiol, when needed. This conversion often involves the enzyme aromatase, which transforms androgens like androstenedione into estrone. Estrone contributes to bone health by helping maintain bone density. It also influences reproductive health and female sexual characteristics.
Reasons for Estrone Testing
Healthcare providers may order an estrone blood test for several clinical reasons. One common indication is to evaluate menopausal status, especially in postmenopausal individuals, as estrone levels become more prominent after ovarian function declines.
Estrone testing is also used to monitor hormone replacement therapy (HRT) to ensure estrogen levels remain within a therapeutic range. It can also investigate abnormal uterine bleeding or irregular menstrual cycles. Estrone levels can be assessed for individuals at risk of osteoporosis, as estrogen plays a role in maintaining bone density. The test can also aid in evaluating certain hormone-sensitive cancers, such as breast and endometrial cancer. It may also be part of a broader hormone panel.
Understanding Your Estrone Results
Estrone levels naturally vary based on age, sex, and menopausal status, so “normal” ranges are interpreted within these contexts. For postmenopausal women, estrone typically becomes the primary circulating estrogen, and its levels can be higher than in premenopausal women. Your healthcare provider will consider your individual health profile and symptoms when interpreting your specific results.
Higher-than-normal estrone levels can indicate various conditions. Since estrone forms in fatty tissue, obesity can lead to increased estrone production. Certain ovarian or adrenal gland disorders, including some tumors, may also cause elevated estrone. High estrone levels can occur with hormone replacement therapy or oral contraceptives. Elevated estrone levels have been linked to an increased risk for certain hormone-sensitive cancers, such as breast and endometrial cancer.
Conversely, lower-than-normal estrone levels might suggest conditions such as primary ovarian insufficiency, where ovaries prematurely stop producing hormones. Certain pituitary disorders or conditions like anorexia nervosa, characterized by low body fat, can also result in reduced estrone levels. Extreme exercise or malnutrition can also contribute to lower estrogen levels. Low estrone levels may contribute to symptoms such as fatigue, mood swings, hot flashes, and a reduced sex drive, particularly in postmenopausal individuals. It is important to discuss your estrone test results with a healthcare professional.
Getting an Estrone Blood Test
Undergoing an estrone blood test is a straightforward procedure. A healthcare professional typically collects a blood sample from a vein in your arm. The sample is then sent to a laboratory for analysis.
Generally, no specific preparation, such as fasting, is required. However, confirm any specific instructions with your doctor or the pathology collection center, especially if other blood tests are being performed concurrently. Inform your healthcare provider about any medications or supplements you are taking, including hormone therapies or biotin, as these can influence the test results. For menstruating individuals, the timing of the blood sample collection may correlate with their menstrual cycle, as estrone levels can fluctuate throughout the month.