About the Test
Purpose of the test
A progesterone test is used in several circumstances:
- To determine the cause of infertility
- To track ovulation
- To help diagnose an ectopic or failing pregnancy
- To monitor the health of a pregnancy
- To monitor progesterone replacement therapy
- To diagnose the cause of abnormal uterine bleeding
What does the test measure?
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. This test measures the level of progesterone in the blood.
Every month, the hormone estrogen causes the lining of the uterus, the endometrium, to grow and replenish itself. A surge in luteinizing hormone (LH) leads to the release of an egg from one of two ovaries (ovulation). Then a corpus luteum (tissue mass) 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. When a fertilized egg is implanted in the uterus, the corpus luteum continues to create progesterone, forming a trophoblast that produces human chorionic gonadotropin (hCG).
After several weeks, the placenta replaces the corpus luteum as the main source of progesterone, producing relatively large amounts of the hormone throughout the rest of a normal pregnancy.
Progesterone is also produced in males but at a much lower level. Its function involves the development of sperm.
When should I get this test?
There are several instances in which you might consider progesterone testing:
- At specific times during a woman’s menstrual cycle to determine whether/when she is ovulating (releasing an egg from an ovary)
- During early pregnancy when symptoms suggest an ectopic or failing pregnancy
- Throughout a high-risk pregnancy to help determine placenta and fetal health
- Periodically when you are receiving progesterone replacement therapy
- When a woman has abnormal uterine bleeding
Finding a Progesterone Test
How can I get a progesterone test?
Progesterone testing is usually performed at a doctor’s office or another medical setting like a hospital or lab. These tests are normally ordered by a doctor but may be available without orders from your doctor at a walk-in lab.
Can I take the test at home?
A progesterone test can be taken at home with a saliva test kit. Alternatively, you can have a blood sample collected in-person at a LabCorp facility.
How much does the test cost?
The cost of a progesterone test will vary depending on factors such as where the test is done and whether you have health insurance. When ordered by a doctor, insurance typically covers the test, although you may have to pay a copay or deductible. Your doctor’s office, lab, and health plan can provide information about any out-of-pocket costs that may be your responsibility.
Taking a Progesterone Test
The progesterone test usually requires a blood sample, which is usually taken from your arm in a doctor’s office, health clinic, hospital, or lab. However, a saliva sample can also be accepted depending on the type of test available.
Before the test
Usually, no special preparation is required for a progesterone test. Your doctor will tell you if you need to stop taking any medications or supplements before the test.
During the test
A blood sample is taken from a vein in your arm. The person taking the sample may tie a band around your upper arm and will clean the area where the needle will be inserted into your skin. A small amount of blood is drawn into a tube. You may feel a slight sting when the needle enters your skin.
The process of taking a blood sample usually takes less than three minutes.
After the test
At a doctor’s office or lab, you will be asked to apply gentle pressure to the site with a bandage or a piece of gauze after the needle is withdrawn. This will help stop bleeding and may prevent bruising. Next, the site will be bandaged. You may resume your normal activities following the test.
A blood draw is a very low-risk procedure. You may have slight bruising at the site where the blood sample was taken.
Progesterone Test Results
Receiving test results
The doctor who ordered your progesterone test may share the results with you, or you may be able to access them through an online patient portal. Progesterone results are usually available within a few business days.
Interpreting test results
Interpretation of progesterone test results depends on the reason for testing and requires knowledge of the point at which a woman is in her menstrual cycle or pregnancy. Progesterone levels usually start to increase when an egg is released from the ovary. They rise for several days and either continue to rise with early pregnancy or fall to initiate menstruation.
If progesterone levels do not rise and fall monthly, a woman may not be ovulating nor having regular menstrual periods. This may be a cause of infertility.
The pregnancy may be ectopic and/or failing if levels do not normally rise during early pregnancy. If serial measurements do not show increasing progesterone levels over time, there may be problems with the viability of the placenta and fetus.
Low levels of progesterone may be associated with:
- Ectopic pregnancy
- Fetal death/miscarriage
- Decreased function of ovaries
- Lack of menstruation (amenorrhea)
Increased progesterone levels 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
- Adrenal cancer
- Congenital adrenal hyperplasia (CAH)
You may want to ask your doctor the following questions:
- Could any medications I may be taking affect my progesterone level?
- If I am menopausal and on hormone replacement therapy (HRT), is there ever a need to monitor my progesterone level?
- Are there any follow-up tests I should do?