Since progesterone levels vary predictably 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 will be lower than expected), although this will not differentiate between the two conditions. Progesterone levels also may be measured throughout a high-risk pregnancy to help evaluate placenta and fetal health.
Progesterone levels may be monitored in women who have trouble maintaining a pregnancy, as low levels of the hormone can lead to miscarriage. 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.
In women who are not pregnant, progesterone levels may be used, along with other tests, to help determine the cause of abnormal uterine bleeding.
What does the test result mean? NOTE: This test has no single number that identifies an abnormal result.
Your lab report (see a sample report) should include
a range of numbers (reference range) that identifies what is expected for you based on
your age, sex, and the method used in that laboratory. You can find more information
about expected results at Reference Ranges
and What They Mean. Lab Tests Online strongly recommends that you discuss the meaning of your test results with your doctor.
Interpretation of progesterone test results 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.
Levels of progesterone will be naturally higher during pregnancies that involve multiples (twins, triplets, etc.) than those in which there is only one fetus.
Increased progesterone levels also are seen occasionally with luteal ovarian cysts, molar pregnancies, and with a rare form of ovarian cancer.
Increased levels are occasionally due to an overproduction of progesterone by the adrenal glands.
In late pregnancy, low levels of progesterone may be associated with toxemia.
This article was last reviewed on May 15, 2006.
This page was last modified on April 8, 2009.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
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