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Estrogens are the hormones responsible for female sexual features such as breast development and the menstrual cycle. An estrogen test measures the level of the most important estrogens (estradiol, estriol, and estrone), usually through a blood sample.
In women, estrogens are produced mainly in the ovaries (and the placenta during pregnancy). Small amounts are also produced by the adrenal glands. In men, small amounts of estrogens are produced by the adrenal glands and testicles. Small amounts of estrone are made throughout the body in most tissues, especially fat and muscle. This is the major source of estrogen in women who have gone through menopause.
Function; Reasons For Use
Estradiol is the estrogen that is most commonly measured in women who are not pregnant. The amount of estradiol in a woman's blood varies throughout her menstrual cycle. After menopause, estradiol production drops to a very low but constant level.
Estriol levels are usually measured during pregnancy to determine the likelihood of the fetus having Down's syndrome or other birth defects. Estriol can be detected as early as the 9th week of pregnancy, and its levels increase until delivery. This measurement is often included in a maternal serum "triple" or "quadruple" screening test.
Usually performed at between 16 and 18 weeks, these tests measure the amounts of three or four substances in a pregnant woman's blood. The triple screen measures alpha-fetoprotein (AFP), beta human chorionic gonadotropin (beta-HCG), and unconjugated estriol (uE3). The quad screen measures these substances as well as the hormone inhibin-A. The levels of these substances, along with a woman's age and other factors, help estimate the risk that her child may have certain problems or birth defects.
Estrone may be measured in women who have gone through menopause to determine their estrogen levels. It may also be measured in men or women (through a urine sample) as part of a total estrogen value when a tumor of the ovaries, testicles, or adrenal glands may be present.
A test for estrogen in the blood is carried out for reasons such as:- Help determine whether a woman's reproductive organs are functioning so she can become pregnant. Because estradiol varies widely during the menstrual cycle, it may be tested only in the third sample of a 3-day series to determine the ovaries' ability to produce eggs.
- Help determine whether menopause has occurred. After menopause, the level of estrogens in the blood decreases to a very low level. This test is sometimes done before hormone replacement therapy is started. Follicle-stimulating hormone (FSH) levels are also commonly measured to determine whether menopause has occurred.
- Help detect fetal birth defects (especially Down syndrome) during pregnancy. When the test for estrogens is combined with alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG), it is called a triple test. Other blood tests and fetal ultrasound may be done also.
- Help detect fetal distress in high-risk pregnancies.
- Evaluate abnormal sexual development. In girls or women, these conditions might include early or delayed puberty, excessive menstrual bleeding, or lack of menstrual bleeding (amenorrhea). Measuring estrogen levels can help evaluate estrogen-producing tumors of the ovaries in girls before menstruation starts and in women after menopause.
- Explain abnormal sexual characteristics in men, such as enlarged breasts (gynecomastia). This test can also help detect the presence of estrogen-producing tumors growing in the testicles.
- Monitor therapy with fertility medications (such as Gonal-F, Follistim, or Repronex). Estradiol levels may be monitored before and during treatment with medications that are given to stimulate ovulation. Estradiol levels may also be monitored with assisted reproductive technology (ART) procedures.
Directions
Women who are menstruating should note where they are in their menstrual cycle and give that information to the health professional collecting the blood sample.
Expected Outcome
When it comes to interpreting the results, normal values may vary widely from lab to lab and depend to a large extent on gender, age, menopausal status and pregnancy. Other factors include women undergoing Hormone Replacement Therapy (HRT); hormonal birth control such as pills or patches; having had a test involving radioactive substances within the previous week; the medication clomiphene (Serophene, Clomid); corticosteroids, such as dexamethasone (Decadron); high levels of sugar in the urine caused by diabetes.
High values:- Estradiol:
- Common in women who are having their ovaries stimulated to treat infertility.
- In a woman can indicate a tumor of the ovaries or adrenal glands. (These tumors can produce estradiol.)
- In a man can indicate a tumor of the testicles or adrenal glands.
- Can indicate serious liver disease (cirrhosis) in both men and women.
- Estriol:
- Can be caused by a pregnancy with more than one fetus (such as twins or triplets).
- High estrogen levels can indicate early (precocious) puberty.
Low values:- Estradiol:
- In women this can indicate reduced function of the ovaries, possibly caused by a failure of an ovary to develop properly (Turner's syndrome) or because of a drop in pituitary gland activity.
- May be caused by anorexia nervosa.
- May indicate that menopause has occurred.
- Estriol:
- Levels that begin to decrease during pregnancy, or that do not rise, may indicate a problem with the fetus or placenta.
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Test Estrogen Level can help with the following:
KEY | | Likely to help |  | | Avoid absolutely |
GLOSSARY
Adrenal (Adrenal Gland, Adrenal Glands, Adrenals)
The adrenal glands sit on top of each kidney and consist of an outer cortex and an inner medulla. Of the 50 or so hormones the adrenals make, only cortisone and adrenaline are recognized by most people. Some of these hormones must be produced to preserve life, while others help resist stress. Other hormones from the adrenals control normal energy output (along with the thyroid) and govern the breakdown of stored energy into quick energy sources. The medulla produces epinephrine and norepinephrine, which are specifically designed to help the body deal with stressful situations. The adrenals control the body's potassium/sodium balance, which is vital for energy production. They also produce sex hormones in minute amounts, which is important for later years when the gonads drop or cease their production.
Amenorrhea
Absence or suppression of menses. Primary amenorrhea is the failure to begin menses by age 16, secondary amenorrhea is tardy menses (from pregnancy, stress, dieting, illness or intensive physical training) in the previously menstruating woman.
Anorexia Nervosa (Anorexia)
An eating disorder characterized by excess control - a morbid fear of obesity leads the sufferer to try and limit or reduce their weight by excessive dieting, exercising, vomiting, purging and use of diuretics. Sufferers are typically more than 15% below the average weight for their height/sex/age and typically have amenorrhea (if female) or low libido (if male). 1-2% of female teenagers are anorexic.
Cirrhosis (Liver Cirrhosis)
A long-term disease in which the liver becomes covered with fiber-like tissue. This causes the liver tissue to break down and become filled with fat. All functions of the liver then decrease, including the production of glucose, processing drugs and alcohol, and vitamin absorption. Stomach and bowel function, and the making of hormones are also affected.
Corticosteroid (Corticosteroids)
Steroid hormone produced by the adrenal cortex.
Diabetes Mellitus (Diabetes, Diabetic, Diabetics)
A disease with increased blood glucose levels due to lack or ineffectiveness of insulin. Diabetes is found in two forms; insulin-dependent diabetes (juvenile-onset) and non-insulin-dependent (adult-onset). Symptoms include increased thirst; increased urination; weight loss in spite of increased appetite; fatigue; nausea; vomiting; frequent infections including bladder, vaginal, and skin; blurred vision; impotence in men; bad breath; cessation of menses; diminished skin fullness. Other symptoms include bleeding gums; ear noise/buzzing; diarrhea; depression; confusion.
Estrogen (Oestrogen)
One of the female sex hormones produced by the ovaries.
Gland (Glands)
The glandular system is one of the most important and complicated systems of the body. Gland tissue can be either an organ or general tissue that secretes chemicals and there are two types of gland: exocrine and endocrine. Those glands which secrete chemicals through tubules or ducts are called exocrine and include sweat, tear and salivary glands. Ductless glands - part of the endocrine system - secrete special chemicals (hormones) directly into the blood.
Gynecomastia
Occurs when the male breast is enlarged. The size can vary from a slight puffiness to full female-like breasts. It literally means "female-like breasts".
Hormones (Hormone)
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Liver (Hepatic)
The largest and one of the most complex organs of the body, the liver is responsible for much of the metabolism of fats, proteins and carbohydrates. It is the site of much of the body's detoxification. It is connected very closely with digestion and the regulation of blood sugar, among many other functions. Found behind the ribs on the right side of the abdomen, it has many important functions such as removing harmful material from the blood, making enzymes and bile that help digest food, and converting food into substances needed for life and growth. Hepatic: Pertaining to the liver.
Menopause (Menopausal)
The cessation of menstruation (usually not official until 12 months have passed without periods), occurring at the average age of 52. As commonly used, the word denotes the time of a woman's life, usually between the ages of 45 and 54, when periods cease and any symptoms of low estrogen levels persist, including hot flashes, insomnia, anxiety, mood swings, loss of libido and vaginal dryness. When these early menopausal symptoms subside, a woman becomes postmenopausal.
Menstruation (Menses, Menstrual, Menstrual Cycle, Menstrual Cycles, Menstrual Flow, Menstrual Phase, Monthly Cycle)
The periodic discharge of blood, tissue fluid and mucus from the endometrium (lining of the uterus) that usually lasts from 3 - 5 days. It is caused by a sudden reduction in estrogens and progesterone.
Ovary (Ovaries)
Ovaries are about the size of an almond and lie on either side of the lower abdomen beside the uterus. They usually produce one egg each month and whether the egg is fertilized or not, the reproductive process follows a monthly cycle, with constant changes in various hormone levels, preparing another opportunity for conception. The ovary is responsible for most of the estrogen production in women. At menopause (sometime after middle-age), egg production ceases and hormone levels drop significantly.
Panic Attack (Panic Attacks)
A brief, irrational episode of fear that is perceived as so real that an individual may be driven to escape from the place or situation where it occurs. The attack is sudden and increases in severity until it leaves, usually within ten minutes. Panic attack symptoms are numerous and involve both mental and physical signs and symptoms. A panic attack can occur in other anxiety states such as agoraphobia and with certain activities and places. It may occur spontaneously without an apparent cause.
Pituitary (Pituitary Gland)
The pituitary gland is a small (half-inch), bean-shaped organ that hangs down from the lower center of the brain on a stalk attached to another gland, the hypothalamus. Weighing less than one gram, the pituitary gland is often called the "master gland" since it controls the secretion of hormones by other endocrine glands. It regulates many body activities, and is partitioned into front and back lobes. The front lobe is stimulated by the hypothalamus, and produces any one of six different hormones that in turn stimulate the thyroid, adrenal and reproductive glands, and also breast milk production.
Serum
The cell-free fluid of the bloodstream. It appears in a test tube after the blood clots and is often used in expressions relating to the levels of certain compounds in the blood stream.
Syndrome
A medical condition characterized by a collection of related symptoms (what the patient feels) and signs (what a doctor can observe or measure).
Testicles (Testicle, Testicular)
Egg-shaped sex glands in the scrotum that secrete male hormones such as testosterone, and produce sperm.
Ultrasound
Ultrasound testing uses sound waves projected into the body to produce an image of internal organs, structures, tumors, etc. In this procedure, a gel is applied to the patient's skin, and a small device that emits ultrasonic pulses is slowly passed over the area. The sonic image produced is viewed on a monitor.
Last updated: Jun 22, 2008
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