What is a progesterone test?

A progesterone test measures the level of progesterone in the blood. Progesterone is a hormone made by a woman’s ovaries. Progesterone plays an important role in pregnancy. It helps make your uterus ready to support a fertilized egg. Progesterone also helps prepare your breasts for making milk.

Progesterone levels vary during a woman’s menstrual cycle. The levels start out low, then increase after the ovaries release an egg. If you become pregnant, progesterone levels will continue to rise as your body gets ready to support a developing baby. If you do not become pregnant (your egg is not fertilized), your progesterone levels will go down and your period will begin.

Progesterone levels in a pregnant woman are about 10 times higher than they are in a woman who is not pregnant. Men also make progesterone, but in much smaller amounts. In men, progesterone is made by the adrenal glands and testes.

Other names: serum progesterone, progesterone blood test, PGSN

What is it used for?

A progesterone test is used to:

• Find the cause of a woman’s infertility (the inability to make a baby)
• Find out if and when you are ovulating
• Find out your risk of a miscarriage
• Monitor a high-risk pregnancy
• Diagnose an ectopic pregnancy, a pregnancy that grows in the wrong place (outside the uterus). A developing baby can’t survive an ectopic pregnancy. This condition is dangerous, and sometimes life-threatening, for a woman.

Why do I need a progesterone test?

You may need this test if you are having trouble getting pregnant. A progesterone test can help your health care provider see if you are ovulating normally.

If you are pregnant, you may need this test to check the health of your pregnancy. Your provider may recommend a progesterone test if you are at risk for miscarriage or other pregnancy complications. Your pregnancy may be at risk if you have symptoms such as abdominal cramps or bleeding, and/or a previous history of miscarriage.

What happens during a progesterone test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don’t need any special preparations for a progesterone test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If your progesterone levels are higher than normal, it may mean you:

• Are pregnant
• Have a cyst on your ovaries
• Have a molar pregnancy, a growth in the abdomen that causes symptoms of pregnancy
• Have a disorder of the adrenal glands
• Have ovarian cancer

Your progesterone levels may be even higher if you are pregnant with two or more babies.

If your progesterone levels are lower than normal, it may mean you:

• Have an ectopic pregnancy
• Had a miscarriage
• Are not ovulating normally, which can cause fertility problems

If you have questions about your results, talk to your health care provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a progesterone test?

Because progesterone levels change throughout your pregnancy and menstrual cycle, you may need to be retested several times.