Serum progesterone is a test to measure the amount of progesterone in the blood. Progesterone is a hormone produced mainly in the ovaries.
Progesterone plays a key role in pregnancy. It is produced after ovulation in the second half of the menstrual cycle. It helps make a woman's uterus ready for a fertilized egg to be implanted. It also prepares the uterus for pregnancy by inhibiting the uterine muscle to contract and the breasts for milk production.
A blood sample is needed. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.
Many medicines can interfere with blood test results.
You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.
This test is done to:
Progesterone levels vary, depending on the timing when the test is done. Blood progesterone levels start to rise midway through the menstrual cycle. It continues to rise for about 6 to 10 days, and then falls if the egg is not fertilized.
Levels continue to rise in early pregnancy.
The following are normal ranges based upon certain phases of the menstrual cycle and pregnancy:
Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements.
Higher-than-normal levels may be due to:
Lower-than-normal levels may be due to:
Reviewed By: Anita Sit, MD, Department of OB/GYN, Santa Clara Valley Medical Center, San Jose, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.