Both men and women produce progesterone. However, it is produced mainly in the ovaries, which means that women have more than men.
In men, progesterone’s role is in spermatogenesis (sperm creation) among other roles.
In women, this hormone helps prepare the uterus for a fertilized egg. Once a woman is pregnant, progesterone helps her remain pregnant. Progesterone inhibits milk production during pregnancy and the drop in progesterone at the time of labor helps to trigger milk production.
The serum progesterone test is commonly ordered when a woman has trouble getting pregnant. It can give doctors an indication of whether she is ovulating. This, in turn, can provide insight into fertility problems. Your doctor might also choose to perform this test if you are pregnant and he or she thinks you might be at risk of miscarriage or ectopic pregnancy. The serum progesterone test is sometimes performed if you have had miscarriages or a stillbirth in the past or if you have bleeding from your uterus.
All this test involves on your part is allowing a healthcare provider to draw a sample of your blood. First, he or she will clean the skin directly over a vein. Next, he or she will insert a needle through the cleaned skin into your vein. He or she will draw blood through the needle into a vial or tube, and then send it to a laboratory for testing.
In women, progesterone is low at the beginning of the menstrual cycle. It peaks several days after ovulation, and then falls back to low levels unless the woman gets pregnant.
Serum progesterone is measured in nanograms per deciliter (ng/dL). Normal results are complicated because they depend greatly on age, gender, pregnancy, and menstrual cycle.
In general, normal results are in the following ranges:
- women before ovulating, postmenopausal women, and men: under 1 ng/mL
- women mid-cycle: 5 to 20 ng/mL
- pregnant women:
- 1st trimester: 11.2 to 90 ng/mL
- 2nd trimester: 25.6 to 89.4 ng/mL
- 3rd trimester: 48.4 to 42.5 ng/mL
It’s normal to have elevated progesterone levels if you are pregnant. In other, rarer cases, high progesterone may be caused by:
- adrenal cancer
- congenital adrenal hyperplasia, a group of disorders that affect the adrenal gland; typically people with this disorder lack an enzyme that the adrenal gland needs to make the hormones cortisol and aldosterone. Cortisol is often referred to as the stress hormone because it is released when you are stressed, but its primary job is to increase blood sugar. Aldosterone is a hormone involved in helping the kidneys to function properly.
- ovarian cancer
Low progesterone may be caused by:
- ectopic pregnancy
- failure to ovulate
- fetal death
- lack of periods
Keep in mind that progesterone levels can fluctuate greatly over the course of a single day. For example, Tennessee Reproductive Medicine reports variations from 2 ng/mL to 40 ng/mL in a day. (TRM) In other words, a single, slightly abnormal test result may simply be due to your body’s normal progesterone level fluctuations.
Any time you have your blood drawn, you will probably feel some pain when your healthcare provider inserts the needle into your vein. You might also bleed for a few minutes after the needle is removed. A bruise might develop in the area surrounding the puncture site.
More serious complications are rare. However, they include fainting, vein inflammation, and infection.
Several drugs, including birth control pills and progesterone, can affect the results of the serum progesterone test. Tell your doctor about any medications you’re taking. This will give him or her a chance to instruct you to stop taking any that will interfere with your serum progesterone test results.