Test Overview

An estrogen test measures the level of the most important estrogen hormones in a blood or urine sample. It measures estradiol, estriol, and estrone.

• Estradiol is the most common type of estrogen measured for non-pregnant women. The amount of estradiol in a woman's blood varies throughout her menstrual cycle. After menopause, it drops to a very low but constant level.

• Estriol levels are most often measured only during pregnancy. Estriol is produced in large amounts by the placenta. This is the tissue that links the fetus to the mother. Estriol can be found as early as the 9th week of pregnancy. The levels keep rising until delivery. Estriol can also be measured in urine.

• Estrone may be measured in women who have gone through menopause. It's done to find out their estrogen levels. It also may be measured in men or women who might have cancer of the ovaries, testicles, or adrenal glands.

Both men and women make estrogen hormones. Estrogens are responsible for female sexual development and function, such as breast development and the menstrual cycle. In women, estrogens are made mainly in the ovaries and in the placenta during pregnancy. Small amounts are also made by the adrenal glands. In men, small amounts of estrogens are made 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.

For pregnant women, the level of estriol in the blood is used in a serum quad screening test. In most cases, this test is done between 15 and 22 weeks of pregnancy. It checks the levels of four substances in a pregnant woman's blood. They are the hormone inhibin A, alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and a type of estrogen (unconjugated estriol, or uE3). The levels of these substances—along with a woman's age and other factors—help the doctor figure out the chance that the baby may have certain problems or birth defects.

Why It Is Done

A test for estrogen is done to:

• Help find fetal birth defects (especially Down syndrome) during pregnancy. When the test for estriol is done with hormone inhibin A, alpha-fetoprotein (AFP), and human chorionic gonadotropin (hCG), it is called a quad screen test. Other blood tests and fetal ultrasound may be done as well.
• Check for estrogen-producing tumours of the ovaries in girls before menstruation starts and in women after menopause.
• Help explain enlargement of breast tissue in men (gynecomastia). This test can also help find out if there are estrogen-producing tumours growing in the testicles.
• Monitor treatment with fertility medicines.

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How To Prepare

You do not need to do anything special to prepare for this test.

How It Is Done

A health professional uses a needle to take a blood sample, usually from an arm.

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How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

Results are usually available within 24 hours.

Normal

For girls and women between puberty and menopause, estrogen levels vary throughout the menstrual cycle.

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

Many conditions can change estrogen levels. Your doctor will talk with you about any important abnormal results as they relate to your symptoms and past health.

High values

High values may be caused by:

• Ovarian stimulation used to treat infertility (for example, before in vitro fertilization).
• Cancer, such as cancer of the ovaries, testicles, or adrenal glands.
• Serious liver disease (cirrhosis).
• A pregnancy with more than one fetus, such as twins or triplets.
• Early puberty.

Low values

Low values may be caused by:

• Problems with ovarian function. This can be caused by a failure of an ovary to develop properly (Turner's syndrome) or because of a drop in pituitary gland activity.
• Anorexia nervosa.
• Menopause.
• A problem with the fetus or placenta during pregnancy.