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Serum Progesterone Test: Purpose, Results, and Risks

What is a serum progesterone test?

Progesterone is a hormone that your body produces. Both men and women produce it. But it’s mainly produced in the ovaries, which means women tend to have more of it.

In men, progesterone is involved in the creation of sperm, or spermatogenesis. In women, it helps prepare your uterus for a fertilized egg. If you become pregnant, progesterone helps you remain pregnant.

Progesterone also inhibits your milk production during pregnancy. When you go into labor, your progesterone levels drop, which helps trigger your milk production.

To measure the level of progesterone in your blood, your doctor can order a serum progesterone test. They may order it if you’re having trouble getting pregnant. The results can give them an indication of whether or not you’re ovulating. In turn, this can help them diagnose and manage potential fertility problems.

Your doctor might also order this test if you’re pregnant and they suspect you’re at risk of ectopic pregnancy or miscarriage. Ectopic pregnancy happens when a fertilized egg attaches itself to your fallopian tube, abdominal cavity, or cervix, rather than your uterus. Miscarriage happens when you lose a fetus during early pregnancy. Both cause low progesterone levels.

How should you prepare for a serum progesterone test?

To conduct a serum progesterone test, your doctor will collect a sample of your blood to send to a laboratory.

They may ask you take certain steps to prepare for the test. For example, you should tell your doctor about any medications you’re taking. Some drugs, such as birth control pills and progesterone supplements, can affect the results of your test.

Some drugs, such as blood thinners, can also raise your risk of complications from a blood draw. Your doctor may ask you to stop taking certain medications before you get your blood drawn.

What does a serum progesterone test involve?

Your doctor may collect a sample of your blood in their office or send you to another site to have your blood drawn. The person drawing your blood will start by cleaning an area of your skin directly over a vein.

Next, they will insert a needle into your vein. They will draw blood through the needle into a vial or tube. Then they will send your blood sample to a laboratory for testing.

What are the risks of a serum progesterone test?

Any time you have your blood drawn, you face some risks. For most people, these risk are minor.

You will probably feel some pain when the needle is inserted into your vein. And you might bleed for a few minutes after the needle is removed. A bruise might also develop in the area surrounding the puncture site.

More serious complications are rare. These include fainting, inflammation of your vein, and infection at your puncture site. If you have a bleeding disorder, the risks of a blood draw are higher.

What do your test results mean?

Your serum progesterone level will be measured in nanograms per deciliter (ng/dL). Once your results are ready, the laboratory will send them to your doctor. Normal results can vary, depending on your gender, age, menstrual cycle, and whether or not you’re pregnant.

If you’re a woman who menstruates, your blood progesterone level should be low at the beginning of each menstrual cycle. It should peak several days after you ovulate. Then it should fall back to low levels, unless you’ve become pregnant.

Normal test results

In general, normal serum progesterone test results fall in the following ranges:

  • men, postmenopausal women, and women at the beginning of their menstrual cycle: 1 ng/mL or under
  • women in the middle of their menstrual cycle: 5 to 20 ng/mL
  • pregnant women in their first trimester: 11.2 to 90 ng/mL
  • pregnant women in their second trimester: 25.6 to 89.4 ng/mL
  • pregnant women in their third trimester: 48.4 to 42.5 ng/mL

Abnormal test results

Your test results are considered abnormal if they fall outside the normal ranges. In some cases, a single abnormal test result reflects normal fluctuations in your progesterone levels.

Your progesterone levels can fluctuate a lot, even over the course of a single day. In other cases, abnormally high or low progesterone levels may be a sign of an underlying health problem.

In addition to pregnancy, high progesterone levels can be caused by:

  • ovarian cancer
  • adrenal cancer
  • congenital adrenal hyperplasia, a group of disorders that affect your adrenal gland

Low progesterone levels can be caused by:

  • lack of periods
  • failure to ovulate
  • ectopic pregnancy
  • miscarriage
  • fetal death


Ask your doctor what your test results mean. They can help you understand the potential causes of abnormally high or low progesterone levels. They can also discuss appropriate follow-up steps. Depending on your test results, your doctor may recommend additional tests or treatments.

Content licensed from:

Written by: Gretchen Holm
Medically reviewed on: Aug 22, 2016: University of Illinois-Chicago, College of Medicine

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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