At a Glance
Why Get Tested?
To help determine the cause of infertility, track ovulation, help diagnose an ectopic or failing pregnancy, monitor the health of a pregnancy, and help diagnose the cause of abnormal uterine bleeding
When to Get Tested?
At specific times during a woman's menstrual cycle to determine whether/when she is ovulating; during early pregnancy when symptoms suggest an ectopic or failing pregnancy; throughout pregnancy to help determine placenta and fetal health; and when a woman has abnormal uterine bleeding
Sample Required?
A blood sample drawn from a vein in your arm; a limited number of laboratories can perform this test on saliva.
Test Preparation Needed?
None
The Test Sample
What is being tested?
This test measures the level of progesterone in the blood. Progesterone is a steroid hormone whose main role is to help prepare a woman's body for pregnancy; it works in conjunction with several other female hormones.
On a monthly basis, the hormone estrogen causes the lining of the uterus, the endometrium, to grow and replenish itself, while a surge in luteinizing hormone (LH) leads to the release of an egg from one of two ovaries. A corpus luteum then forms in the ovary at the site where the egg was released and begins to produce progesterone. This progesterone, supplemented by small amounts produced by the adrenal glands, stops endometrial growth and readies the uterus for the possible implantation of a fertilized egg.
If fertilization does not occur, the corpus luteum degenerates, progesterone levels drop, and menstrual bleeding begins. If a fertilized egg is implanted in the uterus, the corpus luteum continues to produce progesterone. After several weeks, the placenta replaces the corpus luteum as the main source of progesterone, creating relatively large amounts of the hormone throughout the rest of a normal pregnancy.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. A limited number of laboratories can perform this test on saliva.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed. The patient's last menstrual period and trimester of pregnancy should be noted.
The Test
How is it used?
Since progesterone levels vary throughout the menstrual cycle, multiple (serial) measurements can be used to help recognize and manage some causes of infertility. Progesterone can be measured to determine whether or not a woman has ovulated, to determine when ovulation occurred, and to monitor the success of induced ovulation.
In early pregnancy, progesterone measurements may be used, along with human chorionic gonadotropin (hCG) testing, to help diagnose an ectopic or failing pregnancy. Progesterone levels may also be ordered to monitor a high-risk pregnancy to help evaluate placenta and fetal health. Decreased levels are seen in ectopic pregnancies and in miscarriages.
If a woman is receiving progesterone injections to help support her early pregnancy, her progesterone levels may be monitored on a regular basis to help determine the effectiveness of that treatment.
Progesterone levels may be ordered, along with other tests such as an FSH, LH, hCG, thyroid tests, clotting tests, and a CBC (Complete Blood Count), to help determine the cause of abnormal uterine bleeding in non-pregnant women.
When is it ordered?
Progesterone levels are measured:
- As part of an infertility assessment, when a woman is having trouble getting pregnant and the doctor wants to verify that she is ovulating normally. The test may be ordered a couple of times during a woman's menstrual cycle to evaluate the change in progesterone concentrations.
- To determine when ovulation has occurred and following drug therapy to induce ovulation
- When symptoms, such as abdominal pain and spotting, suggest an ectopic pregnancy or threatened miscarriage
- To monitor the effectiveness of treatment when a woman requires progesterone injections to help maintain her pregnancy
- Periodically throughout a high-risk pregnancy to monitor placenta and fetal health
- When a non-pregnant woman is experiencing abnormal uterine bleeding
What does the test result mean?
Interpretation of progesterone test results depends on the reason for testing and requires knowledge of where a woman is in her menstrual cycle or pregnancy. Progesterone levels usually start to elevate when an egg is released from the ovary, rise for several days, and then either continue to rise with early pregnancy or fall to initiate menstruation.
If progesterone levels do not rise and fall on a monthly basis, a woman may not be ovulating or having menstrual periods. If levels do not rise normally during an early pregnancy, the pregnancy may be ectopic and/or may be failing. If serial measurements do not show increasing progesterone levels over time, there may be problems with the viability of the placenta and fetus.
Increased progesterone levels also are seen occasionally with:
- Some ovarian cysts
- Non-viable pregnancies known as molar pregnancies
- A rare form of ovarian cancer
- Overproduction of progesterone by the adrenal glands
- Congenital adrenal hyperplasia (CAH)
Low levels of progesterone may be associated with:
- Toxemia late in pregnancy
- Decreased function of ovaries
- Lack of menstruation (amenorrhea)
Is there anything else I should know?
Levels of progesterone will be naturally higher during pregnancies that involve multiples (twins, triplets, etc.) than those in which there is only one fetus.
Taking estrogen and progesterone supplements can affect results.
Common Questions
Ask a Laboratory Scientist
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Related Pages
On This Site
Conditions: Pregnancy, Infertility , Menopause
Elsewhere On The Web
MedlinePlus Medical Encyclopedia: Progesterone
American Society for Reproductive Medicine: Infertility: An Overview, A Guide for Patients
American Society for Reproductive Medicine: Hirsutism and Polycystic Ovarian Syndrome, A Guide for Patients
American Society for Reproductive Medicine: Age and Fertility, A Guide for Patients
National Heart Lung and Blood Institute: Facts About Menopausal Therapy
MedlinePlus Health Topic: Female Reproductive System
National Institutes of Health: Menopausal Hormone Therapy Information
The Hormone Foundation: Pros and Cons for Treatment of Menopause Symptoms
Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 763-764.
Clarke, W. and Dufour, D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 359-360.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 894-897.
Vorvick, L. and Storck, S. (Updated 2009 April 12). Serum progesterone. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003714.htm. Accessed November 2009.
(© 2003). American Society for Reproductive Medicine. Age and Fertility, A Guide for Patients [On-line information]. PDF available for download at http://www.asrm.org/Patients/patientbooklets/agefertility.pdf through http://www.asrm.org. Accessed November 2009.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
Oriel, K. and Schrager, S. (1999 October 1). Abnormal Uterine Bleeding. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/991001ap/1371.html through http://www.aafp.org.
Chen, P. Updated (2001 August 10, Updated). Serum progesterone. MEDLINEplus Health Information [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003714.htm.
Tenore, J. (2000 February 15). Ectopic Pregnancy. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20000215/1080.html through http://www.aafp.org.
NHLBI (2002). The Women's Health Initiative. New Facts About: Estrogen/Progestin Hormone Therapy. National Institutes of Health, National Heart, Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/whi/hrtupd/ep_facts.htm through http://www.nhlbi.nih.gov.
ARUP. Progesterone. ARUP's Guide to Clinical Laboratory Testing (CLT) [On-line information]. Available online at http://www.aruplab.com/guides/clt/tests/clt_148b.htm through http://www.aruplab.com.
Spengler, R. (2000 October 30, updated). Progesterone. WebMD [on-line information]. Available online at http://my.webmd.com/encyclopedia/article/1689.52570 through http://my.webmd.com.
NCI (2002 July 16). Questions and Answers: Use of Hormones After Menopause. National Cancer Institute, News from the NCI [On-line press release]. Available online at http://newscenter.cancer.gov/pressreleases/estrogenplus.html through http://newscenter.cancer.gov.
Merck. Hormones and Reproduction. The Merck Manual of Medical Information - Home Edition [On-line information]. Available online at http://www.merck.com/pubs/mmanual_home/sec22/232.htm through http://www.merck.com.
