Is Your Progesterone Level Too Low or Too High? What Does Your Number Mean?
Progesterone is the hormone used to confirm that a woman ovulated. Interpreting progesterone levels can be confusing. Finally, a clear explanation by a fertility expert.
What does this progesterone level mean?
Here is a scenario that happens a lot. You are trying to become pregnant, your doctor recommends that you have a progesterone blood test to see if you have ovulated. You get some number back like 5 or 10 or 50. What does it mean? I see patients and even other doctors make mistakes in interpreting progesterone levels. I will make you an expert at understanding progesterone.
Progesterone levels in women who don't ovulate
In order to understand what your progesterone levels mean, you need to first understand two pictures. Here's the first picture.
In women who never ovulate, progesterone levels are low all of the time. Low, however, does not mean zero! There is always a little bit of progesterone being produced by the ovaries and the adrenal glands.
Progesterone levels in women who do ovulate
Here is the second picture.
In women who do ovulate, progesterone levels in women change during the month. Before a woman ovulates, progesterone levels in her blood are low. After a woman ovulates, progesterone levels increase. Progesterone levels peak about a week later. Eventually, in the absence of pregnancy, progesterone levels will drop. This is what causes the next period to come.
With that as a background, let's explore what different progesterone levels could mean.
Low progesterone = failure to document ovulation
A progesterone level less than 2.5 means ovulation has not been documented. There are four different possibilities for this.
Four Possibilities for why progesterone levels could be low
Possibility #1: You might be someone who ovulates, but the blood was drawn before ovulation. A progesterone blood test done any time in this range will be low.
Possibility #2: You might have ovulated, but the blood was drawn too soon after ovulation, before enough progesterone has been produced to get the levels up. If this has happened, a repeat blood test one week later should show a progesterone level consistent with ovulation.
Possibility #3: You might have ovulated, but the blood was drawn too close to the time of the next period. Remember, if you don't get pregnant, progesterone levels will drop and eventually will be less than 2.5. If you get your period within a few days after your blood test, be suspicious that the blood was drawn at the wrong time.
Possibility #4: You might be somebody who just doesn't ovulate.
What do progesterone levels less than 10 mean?
On the other hand, a progesterone level of 2.5 or more means ovulation has happened. Some patients (and frankly some doctors) are worried about progesterone levels between 2.5 and 10. I've often heard some doctors tell patients that a progesterone level less than 10 means they didn't ovulate. This is wrong! A level over 2.5 means ovulation happen.
Reasons why progesterone level might be less than 10
There are few reasons why a progesterone level might come back less than 10.
Reason #1: Just as I discussed earlier, the blood might have been drawn too soon after ovulation or too close to the next period.
Reason #2: Progesterone levels fluctuate. If you take blood every 15 minutes from a woman who has ovulated, you will see the levels fluctuate all over the place. Some of the levels are less than 10, some are higher than 10. The lesson here is that if your doctor takes your blood one time, you can tell for sure if ovulation happened but it is impossible to say whether your levels are low or high because they change too much.
Here are some frequently asked questions about progesterone levels:
Can you still become pregnant if you ovulated and your progesterone level is less than 10?
Answer - Yes. As long as you ovulated, pregnancy is possible.
Are you more likely to get pregnant if your progesterone level is higher? In other words, are you more likely to get pregnant if your progesterone level is 25 compared to say a level of 15?
Answer - No! There is no evidence that shows that a higher progesterone level makes it easier to get pregnant.
Is a progesterone level a good way to predict whether you will have a miscarriage?
Answer - No! There is too much fluctuation in progesterone levels to make it a useful test to predict miscarriage.
Can you tell if you are pregnant based on your progesterone level alone?
Answer - No! A high progesterone level can occur even if you are not pregnant. You need to do a pregnancy test to tell whether you are pregnant.