Definition of Serum progesterone:

Serum progesterone is a test to measure the amount of progesterone in the blood. Progesterone is a hormone produced mainly in the ovaries.

In women, progesterone plays a vital role in pregnancy. After an egg is released by the ovaries (ovulation), progesterone helps make the uterus ready for implantation of a fertilized egg. It prepares the womb (uterus) for pregnancy and the breasts for milk production.

Men produce some amount of progesterone, but it probably has no normal function except to help produce other steroid hormones.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture.

How to prepare for the test:

Your health care provider may tell you to stop taking drugs that may affect the test. Drugs that can interfere with the test include progesterone and birth control pills.

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test is done to:

• Determine if a woman is ovulating
• Evaluate a women with repeated miscarriages, but other diagnostic tests and treatment are more commonly used for this purpose
• Determine the risk of miscarriage or ectopic pregnancy early in pregnancy

Normal Values:

Progesterone levels vary depending on when the test is done. Blood progesterone levels start to rise midway through the menstrual cycle, continue to rise for about 6 to 10 days, and then fall if fertilization does not result.

Levels continue to rise in early pregnancy.

This following are normal ranges based upon certain phases of the menstrual cycle and pregnancy:

• Female (pre-ovulation): less than 1 ng/mL
• Female (mid-cycle): 5 to 20 ng/mL
• Male: less than 1 ng/mL
• Postmenopausal: less than 1 ng/mL
• Pregnancy 1st trimester: 11.2-90.0 ng/mL
• Pregnancy 2nd trimester: 25.6-89.4 ng/mL
• Pregnancy 3rd trimester: 48.4-42.5 ng/mL

Note: ng/mL = nanograms per milliliter

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean:

Higher-than-normal levels may be due to:

• Pregnancy
• Adrenal cancer
• Ovarian cancer
• Congenital adrenal hyperplasia

Lower-than-normal levels may be due to:

• Amenorrhea (no periods)
• Ectopic pregnancy
• Failure to ovulate
• Fetal death
• Possible miscarriage

What the risks are:

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)