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.
Stay tuned and in just a few minutes I will make you
an expert at understanding progesterone. If you stay tuned to the end,
I will also answer some frequently asked questions about progesterone
and tell you how to have a consultation with me.
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. 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.
Okay. With that as a background, let's explore what different progesterone
levels could mean. A progesterone level less than 2.5
means ovulation has not been documented. There are four different possibilities for this
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.
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. 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. Hi! Dr. Morris here. I'm an infertility and
IVF expert near Chicago. In addition to hosting InfertilityTV
every week I am a practicing physician. If you would like to have a one-on-one
consultation with me by video, check out my website: IVF1.com
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