Progesterone

Formal name: Progesterone

Related tests: Estrogens, hCG, FSH, LH

The Test

How is it used?
When is it ordered?
What does the test result mean?
Is there anything else I should know?

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.

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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

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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)

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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.

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