Serum progesterone

Definition

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 prepares the breasts for milk production.

Alternative Names

Progesterone blood test (serum)

How the Test is Performed

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.

How to Prepare for the Test

Many medicines can interfere with blood test results.

• Your health care provider will tell you if you need to stop taking any medicines before you have this test.
• DO NOT stop or change your medicines without talking to your provider first.

How the Test will Feel

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.

Why the Test is Performed

This test is done to:

• Determine if a woman is currently ovulating or has recently ovulated
• Evaluate a woman with repeated miscarriages (other tests are used more commonly)
• Determine the risk for miscarriage or ectopic pregnancy early in pregnancy, (now largely superseded by other diagnostic options)

Normal Results

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:

• Female (pre-ovulation): less than 1 nanogram per milliliter (ng/mL) or 3.18 nanomoles per liter (nmol/L)
• Female (mid-cycle): 5 to 20 ng/mL or 15.90 to 63.60 nmol/L
• Male: less than 1 ng/mL or 3.18 nmol/L
• Postmenopausal: less than 1 ng/mL or 3.18 nmol/L
• Pregnancy 1st trimester: 11.2 to 90.0 ng/mL or 35.62 to 286.20 nmol/L
• Pregnancy 2nd trimester: 25.6 to 89.4 ng/mL or 81.41 to 284.29 nmol/L
• Pregnancy 3rd trimester: 48 to 150 to 300 or more ng/mL or 152.64 to 477 to 954 or more nmol/L

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.

What Abnormal Results Mean

Higher-than-normal levels may be due to:

• Pregnancy
• Ovulation
• Adrenal cancer (rare)
• Ovarian cancer (rare)
• Congenital adrenal hyperplasia (rare)

Lower-than-normal levels may be due to:

• Amenorrhea (no periods as result of anovulation [ovulation does not occur])
• Ectopic pregnancy
• Irregular periods
• Fetal death
• Miscarriage

References

Bulun SE. Physiology and pathology of the female reproductive axis. In: Melmed S, Auchus, RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 17.

Humphreys MA, Branch DW. Recurrent pregnancy loss. In: Lockwood CJ, Copel JA, Dugoff L, Louis J, Silver RM, Resnik R, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 41.