Home › Biomarkers › Progesterone/estradiol ratio
Progesterone and estradiol are two hormones made mainly in the ovaries. A low progesterone level may point to ovulation that does not happen normally, and oestrogen levels that stay too high or too low may point to a problem in your body.[1, 2]
On this page you can read what the progesterone/estradiol ratio is, what the guidelines say about a level that is too low or too high, what affects your level and which levels are best to look at alongside it.
Also known as: progesterone-estradiol ratio, ratio between progesterone and estradiol. At the lab: not applicable.
Progesterone is made mainly in the ovaries. In the second half of your cycle, an ovary releases an egg and your progesterone rises. It gets the lining of your womb ready so that a fertilised egg can implant. If you do not become pregnant, your progesterone falls again and your period starts.[1]
Estradiol is a form of oestrogen. It is made mainly in the ovaries. It helps release an egg each cycle and makes the lining of the womb thicker. It also supports your brain and your bones. A small amount of estradiol is made in the testicles.[2]
The ratio divides your progesterone level by your estradiol level. This lets you see the two hormones side by side in one number.
The two hormones take turns. In the first half of your cycle, oestrogen makes the lining of your womb thicker. In the second half, your progesterone rises and gets that lining ready for a fertilised egg.[1]
If you are struggling to get pregnant, a progesterone test can show whether your ovaries are releasing eggs in a normal way.[1]
Oestrogens are not only important for reproduction. In everyone, they play a part in cholesterol and blood sugar, in strong bones and muscles and in your concentration. Levels that stay too high or too low can be a sign of a problem in your body.[2]
| Value | Can point to | Who it is for |
|---|---|---|
| High progesterone[1] | A cyst on the ovaries or a problem with the adrenal glands | If you are not pregnant |
| Higher progesterone than expected[1] | Two or more babies | If you are pregnant |
| Low progesterone[1] | Ovulation that does not happen normally, or no period | If you are not pregnant |
| Low progesterone[1] | A lot of stress, the period just before the menopause, or low cholesterol | If you are not pregnant |
| Low progesterone[1] | A miscarriage or a higher risk of one | If you are pregnant |
Source: MedlinePlus (U.S. National Library of Medicine), on the progesterone test. The source gives no numbers and no limits for the ratio itself.[1]
A high ratio comes from a lot of progesterone, little estradiol or both. If you are not pregnant, a high progesterone level may point to a cyst on the ovaries or a problem with the adrenal glands. In women and men, a high progesterone level can be a sign of a condition of the adrenal glands.[1]
A low ratio comes from little progesterone, a lot of estradiol or both. If you are not pregnant, a low progesterone level may point to ovulation that does not happen normally, a condition of the ovaries that causes missed periods, a lot of stress or the period just before the menopause. In men, the oestrogen level changes little over a lifetime. In men, a high level is usually a sign of a condition.[1, 2]
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 rises after ovulation and falls again if you do not become pregnant. Because the level changes throughout your cycle, you may need to be tested more than once. Sometimes you need to know the first day of your last period.[1]
If you become pregnant, your progesterone keeps rising. Once the placenta is fully developed, it makes a large part of the progesterone you need.[1]
Before an oestrogen test, you sometimes need to stop certain supplements and medicines, such as the pill and hormone therapy for the menopause. Tell your healthcare provider about everything you take. Never stop a medicine on your own, only when your healthcare provider tells you to.[2, 1]
Too much of the stress hormone cortisol can affect your body's ability to make progesterone. Oestrogen levels depend on several things, including your age and your sex. In women they change a lot, in men very little.[1, 2]
The progesterone/estradiol ratio is included in BioProfile 121 and 150.[3]
The BioProfile editorial team wrote this page on 7 November 2026 from the sources below, which we read on 7 November 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; once checked, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss an abnormal value with your GP.
