A progesterone test is a blood test. It can help your doctor check on ovulation or possible fertility problems, make sure everything is OK if you’re already pregnant, or help find out why you have abnormal bleeding from your uterus.
Your doctor may call it a “serum progesterone” test. By itself, it’s not enough to diagnose any particular problem. But it could help, along with other tests.
What Is Progesterone?
Progesterone helps control your period and prepares your body to get pregnant, after you ovulate.
If you do get pregnant, additional amounts of progesterone are created, which, among other effects, helps prepare your breasts to eventually make milk.
If you don’t get pregnant, the level of progesterone in your body drops. This, then, helps trigger the beginning of your period.
What Happens in the Test?
You don’t need to do anything to prepare. But it will help if you take note of when your last menstrual period started and ended -- or, if you’re pregnant, how far along you are.
The test itself is simple. Your doctor, physician’s assistant, or another health care professional will insert a needle in a vein in one of your arms and take a bit of blood for testing in a lab.
Your results may be one of these:
Progesterone levels don’t fluctuate regularly. If the test shows that your progesterone levels don’t rise and fall on a monthly basis, as they should, then you may not be ovulating or having regular periods. This could make it harder to get pregnant.
Progesterone levels not increasing: If you are in the early stages of pregnancy but progesterone levels haven’t risen, as expected, this could signal problems, such as a chance of having a miscarriage. Your doctor would need more than this test result to find that out, though.
High levels of progesterone: If you’re not pregnant, but the test shows increased amounts of progesterone, such results are sometimes linked to:
Low levels of progesterone: If the test shows a lower than normal level of progesterone, it could be due to:
- Toxemia -- a condition that can happen late in your pregnancy that could be serious if not treated
- Ovaries not working normally
- You’re not menstruating
If your doctor has you take a progesterone test, it’s possible that you might also get:
- Other blood tests to check on your ability to get pregnant
- An ultrasound to measure the thickness of the lining of your uterus
- A specific blood test, if you’re already pregnant, to figure out if there are problems with the pregnancy.