Hormones
Progesterone
Also known as: P4
CONVERT & COMPARE
ng/mL
=
0.318
nmol/L
=
0.1
µg/L
=
0.1
mcg/L
=
0.1
ug/L
Reference ranges by source
Published adult intervals: 8, from 4 named sources, shown in ng/mL.
SOURCE
SEX
AGE
RANGE
VISUAL
CITE
About Progesterone
A progesterone test measures the level of progesterone in a sample of your blood. Progesterone is a hormone that's made mainly by the ovaries, which are two glands in the female reproductive system that contain eggs.
Each month, progesterone prepares your uterus for pregnancy. During the first half of a normal menstrual cycle, estrogen makes the lining of your uterus grow thicker. In the second half, an ovary releases an egg and your progesterone levels begin to rise. Progesterone gets the lining of your uterus ready for a fertilized egg to attach (implant) and grow into a fetus.
If you don't become pregnant, your progesterone levels will fall. The lining of your uterus will thin, and your uterus will get rid of the extra blood and tissue when your menstrual period begins.
If you become pregnant, progesterone levels will continue to rise to support the pregnancy.
This test can help confirm that ovulation has happened, suggest when in the cycle ovulation occurred, show whether the corpus luteum (the temporary structure left behind after an egg is released) is functioning, and assess how well the placenta is working during pregnancy.
Main source: MedlinePlus ↗
Useful for
Check to see if fertility treatments are working.
Find out your risk of a miscarriage (loss of a pregnancy before 20 weeks).
Help your provider tell whether an early pregnancy is likely to be healthy (viable) or not. Progesterone alone cannot diagnose an ectopic pregnancy (a fertilized egg that grows outside the uterus, which can be a medical emergency); ectopic pregnancy is diagnosed using a combination of an hCG blood test and a transvaginal ultrasound. Progesterone may be used as one piece of information when ultrasound and hCG results are not yet clear.
Check the health of you and your fetus during a high-risk pregnancy.
Help look for ovarian cancer or problems with your adrenal glands. Normally, your adrenal glands make small amounts of progesterone. High levels of progesterone may be a sign of an adrenal gland disorder in both females and males.
Help find the cause of abnormal uterine bleeding.
Main source: MedlinePlus ↗
Interpretation
The meaning of your test results depends on your age, sex, medical history, and where you are in your menstrual cycle or pregnancy. Ask your provider to explain what your results mean for you.
High progesterone levels may also be a sign of a molar pregnancy, which is an abnormal growth of tissue in the uterus. It's caused by a fertilized egg with such severe genetic problems that it cannot become a fetus. The growth can turn into cancer and must be removed.
For general wellness information only. Talk to a clinician about your specific results.
Main source: MedlinePlus ↗
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Related biomarkers
More tests in the hormones category.
Sources
Last updated 2026-05-02
This page presents source-specific reference data and sourced explanations. For general wellness information only. This is not medical advice. For diagnosis or treatment of any condition, talk to a qualified clinician.