Progesterone

Does this test have other names?

Progesterone blood test, serum progesterone

What is this test?

This test measures the level of a hormone called progesterone in your blood.

Your ovaries make progesterone after ovulation. The most important role of progesterone is to get your uterus ready so that it can receive, implant, and support a fertilized egg during pregnancy.

Progesterone levels are often low during the first stage (follicular stage) of your menstrual cycle. Ovulation is when the egg is released into the fallopian tube. After ovulation, progesterone levels go up for about 5 days before going back down. If pregnancy happens, your progesterone levels will slowly rise from the 9th week of pregnancy until the 32nd week. The placenta will begin to make progesterone after 12 weeks to help your pregnancy stay healthy.

Progesterone levels change according to the stage of your menstrual cycle and the stage of your pregnancy. So this blood test may be repeated many times.

Why do I need this test?

You may need this test as part of a fertility study if you are having trouble getting pregnant. A progesterone blood test is the best sign of ovulation.

You may have this test to find out if:

• You are ovulating

• Your ovaries are working the way they should

If you are pregnant, you may have this test to check the health of your pregnancy.

What other tests might I have along with this test?

You may need other blood tests as part of a fertility study. Your healthcare provider may also order an ultrasound to measure the thickness of the lining of your uterus (endometrium).

If you are pregnant, your provider may order a blood test to measure a hormone called human chorionic gonadotropin to help find out if your pregnancy is at risk.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Progesterone levels vary based on when during your menstrual cycle you have it done, and if you have reached menopause.

Progesterone is measured in nanograms per milliliter (ng/mL). Below are ranges that are considered normal: 

• 0.1 to 0.3 ng/mL for prepubescent girls

• 0.1 to 0.7 ng/mL in the follicular stage of the menstrual cycle

• 2 to 25 ng/mL in the luteal stage of the menstrual cycle

• 10 to 44 ng/mL during the first trimester of pregnancy

• 19.5 to 82.5 ng/mL during the second trimester of pregnancy

• 65 to 290 ng/mL during the third trimester of pregnancy

Other conditions can cause abnormal results of a progesterone blood test. For example:

• Increased progesterone during pregnancy can mean that you have twins or an abnormal type of pregnancy called a molar pregnancy.

• Increased progesterone when you are not pregnant could mean you have a type of ovarian tumor called a lipid ovarian tumor, or chorionepithelioma.

• Decreased progesterone during pregnancy could mean that you have a risk for miscarriage (spontaneous abortion).

• Decreased progesterone when you aren't pregnant could mean that you don't have enough female hormones, a condition called hypogonadism.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. 

What might affect my test results?

Certain medicines, such as birth control pills or steroids, may affect your results.

How do I get ready for this test?

You don't need to get ready for this test. Let your healthcare provider know the date of your last menstrual period. Be sure your provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.