Test Overview

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.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

How It Is Done

The health professional drawing blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed. Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Apply a gauze pad or cotton ball over the needle site as the needle is removed.
• Apply pressure to the site and then a bandage.

For a woman who is having problems with her menstrual cycle or who cannot become pregnant, more than one blood sample for progesterone testing may be needed to help identify the problem. A sample may be taken each day for several days in a row.

How It Feels

You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. But many people do not feel any pain or have only minor discomfort once the needle is positioned in the vein.

Risks

There is very little risk of complications from having blood drawn from a vein.

• You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
• In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.
• Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood is drawn.

Results

A progesterone test measures the amount of the hormone progesterone in a blood sample.

Results are usually available within 24 hours.

Normal

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

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 values

High progesterone values may be caused by:

• Pregnancy.
• Cancer of the ovaries or adrenal glands.
• A molar pregnancy.
• Overproduction of hormones by the adrenal glands.

Low values

Low progesterone values may be caused by:

• Problems with ovulation.
• Possible miscarriage.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• The use of hormones, including those containing estrogen or progesterone (such as birth control pills).
• The use of medicines, such as ampicillin and clomiphene.
• The time of day when you have the test. Progesterone levels normally fluctuate during the day.
• Exercise.
• Having a test such as a thyroid scan or bone scan that used a radioactive substance (tracer) within 1 week before the progesterone test.
• Where you are in your menstrual cycle.

What To Think About

• Levels of progesterone are higher during a multiple pregnancy (such as twins or triplets) than during a single pregnancy (only one fetus).
• Progesterone levels vary widely throughout the menstrual cycle. So it is important for your doctor to know the first day of your last menstrual period.

References

Credits