A progesterone test measures the amount of the hormone progesterone in a blood sample. Progesterone is a female hormone produced by the ovaries during release of a mature egg from an ovary (ovulation). Progesterone helps prepare the lining of the uterus (endometrium) to receive the egg if it becomes fertilized by a sperm. If the egg is not fertilized, progesterone levels drop and menstrual bleeding begins.
During pregnancy, the placenta also produces high levels of progesterone, starting near the end of the first trimester and continuing until the baby is born. Levels of progesterone in a pregnant woman are about 10 times higher than they are in a woman who is not pregnant.
Some types of cancer cause abnormal progesterone levels in men and women.
Why It Is Done
A progesterone test is done to:
- Help find the cause of infertility.
- Monitor the success of medicines for infertility or the effect of treatment with progesterone.
- Help determine whether ovulation is occurring.
- Assess the risk of miscarriage.
- Monitor the function of the ovaries and placenta during pregnancy.
- Help diagnose problems with the adrenal glands and some types of cancer.
How To Prepare
You may be asked to stop taking medicines (including birth control pills) that contain estrogen or progesterone, or both, for up to 4 weeks before having a progesterone test.
Tell your doctor if you have had a test that used a radioactive substance (tracer) within the last 7 days. Recent tests such as a thyroid scan or bone scan that used a radioactive tracer can interfere with the test results.
Let your doctor know the first day of your last menstrual period. If your bleeding pattern is light or begins with spotting, the first day is the day of heaviest bleeding.
How It Is Done
A health professional uses a needle to take a blood sample, usually from the arm.
For a woman who is having problems with her menstrual cycle or who can't get pregnant, more than one blood sample may be needed to help find the problem. A sample may be taken each day for several days in a row.
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.
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 are usually available within 24 hours.
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 progesterone levels. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.
High progesterone values may be caused by:
- Cancer of the ovaries or adrenal glands.
- A molar pregnancy.
- Overproduction of hormones by the adrenal glands.
Low progesterone values may be caused by:
- Problems with ovulation.
- Possible miscarriage.
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