Home › Biomarkers › Progesterone
Progesterone is a hormone made mainly in the ovaries. Every month, it prepares your womb for a fertilised egg. A low level can point to ovulation that is not happening normally. A high level can point to a problem with the ovaries or the adrenal glands.[1]
On this page you can read what progesterone is, what the guidelines say about a level that is too low or too high, what affects your level and which other levels are best to look at alongside it.
Also known as: serum progesterone, progesterone blood test, PGSN. At the lab: PRG.
Progesterone is a hormone. You make it mainly in the ovaries, two glands that contain eggs. Your adrenal glands normally make a small amount too.[1]
In the first half of your cycle, oestrogen thickens the lining of your womb. In the second half, an ovary releases an egg and your progesterone starts to rise. It prepares the lining so that a fertilised egg can implant.[1]
If you do not get pregnant, your progesterone falls. The lining thins and your period starts. If you are pregnant, your level keeps rising. Later, the placenta makes much of the progesterone.[1]
A progesterone test can show whether a low level is the reason you are not getting pregnant. This lets your doctor see whether your ovaries are releasing an egg normally.[1]
If you are pregnant, your progesterone is often measured as part of a series of blood tests. The test can help estimate the chance that you will lose your unborn baby early. The test can also help determine whether a fertilised egg is growing outside the womb.[1]
If you are not pregnant, the test can help find the cause of abnormal bleeding from the womb. The test can also help detect a problem with the ovaries or the adrenal glands.[1]
Signs of a low level include irregular periods, hot flushes and poor sleep. Signs of a high level include vaginal dryness and a bloated feeling.[1]
The lab BioProfile works with, Labplusarts, uses a reference range for progesterone of 0.0 to 4.7 nmol/l. The lab calls a level between those limits normal.[2]
| Value | Can point to | Who it is for |
|---|---|---|
| High[1] | a cyst on an ovary, another condition of the ovaries or a problem with the adrenal glands | if you are not pregnant |
| Higher than expected[1] | two or more babies | if you are pregnant |
| Low[1] | ovulation that does not happen normally, no periods, a lot of stress, the time just before the menopause or low cholesterol | if you are not pregnant |
| Low[1] | a fertilised egg outside the womb, or losing your unborn baby early or a high chance of this | if you are pregnant |
Source: MedlinePlus, U.S. National Library of Medicine, on progesterone in people who are or are not pregnant. The source gives no limits in numbers.[1]
If you are not pregnant, a low level can point to ovulation that is not happening normally or to missed periods. It can also point to a condition of the ovaries with missed periods and unpredictable ovulation. A lot of stress, the time just before the menopause and low cholesterol can also play a part. If you are pregnant, a low level can point to a fertilised egg outside the womb, to losing your unborn baby early or a high chance of that, or to another complication.[1]
If you are not pregnant, a high level can point to a cyst on an ovary, another condition of the ovaries or a problem with the adrenal glands, such as a congenital adrenal condition. If you are pregnant and your level is higher than expected, it can point to two or more babies. A high level can also point to an abnormal growth of tissue in the womb, from a fertilised egg that cannot develop into a baby.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Your progesterone changes over the course of your cycle. That is why you sometimes need to know the first day of your last period. You may also need to be tested more than once.[1]
If you are pregnant, your level keeps rising and keeps changing. In that case too, you may need to be tested more often.[1]
A lot of stress can go hand in hand with a low level. Too much of the stress hormone cortisol can affect your body's ability to make progesterone.[1]
Your doctor will tell you whether you need to stop taking a medicine before the test. Never stop a medicine on your own unless your doctor tells you to.[1]
Progesterone is included in BioProfile 121 and 150.[3]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
