The steroid hormone progesterone (S-Prog) is important to a woman’s fertility. The secretion of progesterone begins late in the menstrual cycle when the ovarian follicle develops into the corpus luteum. The purpose of the hormone is to prepare the lining of the uterus so that the fertilised egg can attach to it. The progesterone level is at its highest seven days before the menstrual period. If pregnancy begins, the level of progesterone continues to increase, or alternatively it decreases to start the period.
The secretion of progesterone in the corpus luteum is influenced by luteinising hormone (LH), oestrogen (E2), and chorionic gonadotropin (khorion, Greek for membrane, gonos for seed, offspring; hCG). During pregnancy, the production of the hormone moves from the corpus luteum to the placenta. Progesterone reduces the ability of the uterus to contract during pregnancy.
Men’s testicles and adrenal glands produce low amounts of progesterone.
When should progesterone be measured?
Progesterone is measured when wanting to know whether ovulation takes place during the menstrual cycle and whether corpus luteum function is normal. The corpus luteum is normally developed from an ovarian follicle during the menstrual cycle, when the follicle bursts and the egg is released.
The test is used for investigating the following:
- Timing of ovulation
- Ovulation taking place in fertility treatment
- When suspecting ectopic pregnancy or miscarriage
- In the follow-up to progesterone therapy
- In connection with ovarian insufficiency
What does a progesterone test measure?
The test indicates the level of the progesterone hormone in the blood. The test is often taken when examining the cause of infertility.
How is the progesterone test result interpreted?
Normally, the result is:
Women, follicular phase (ovulation has not yet taken place): <3.0 nmol/l
Women, kuteal phase (after ovulation): 18.0–72 nmol/l
Women, after menopause: < 3.0 nmol/l
Men: <3.0 nmol/l
Some oral contraceptives contain progesterone, which causes inaccurate results.
If the level of progesterone exceeds 25 nmol/l on the seventh day after assumed ovulation, this is a clear indication of a menstrual cycle in which ovulation, or release of the egg, takes place.
If the function of the corpus luteum is to be examined in more detail, the S-PROG test should be done 4–10 days before the start of a new menstrual cycle, three times, three days apart. When the sum of the progesterone in the three measurements is >60 nmol/l, corpus luteum function is considered to be normal.
Please contact your physician or other healthcare professional if you suspect an illness or need help interpreting the results.
The reference values of this examination have changed 11.10.2021. You will find your own result's reference values from My LOUNA in touch with the graph.
What can cause elevated progesterone values?
The level of progesterone normally varies during the menstrual cycle. The level increases during ovulation and is at its peak in the “luteal phase” of the menstrual cycle. If the egg is fertilised, the secretion of progesterone continues to be high during the pregnancy.
What can cause decreased progesterone values?
If the level of progesterone does not increase and decrease monthly, the woman may lack ovulation or periods. If the level of progesterone does not increase in early pregnancy, the pregnancy can fail or it is an ectopic pregnancy. Low progesterone levels can make it more difficult to get pregnant.
The most typical additional progesterone tests:
- Anti-Müllerian hormone indicates the functioning of the ovaries (S-AMH)
- Follicle stimulating hormone affects the growth and maturation of eggs (1422 S-FSH)
- Luteinising hormone regulates gametes and sex hormones (2265 S-LH)
SYNLAB test list: Progesterone (S-Prog) https://www.yml.fi/tuotekuvaus_show.php?tuotenro=304
LabTest online: Progesterone Test https://labtestsonline.org.uk/tests/progesterone-test
Duodecim Käypä hoito: Progesteroni ja synnytys https://www.kaypahoito.fi/sll32760
Fasting is not required
This examination does not require fasting