Progesterone is a naturally produced hormone that is made by the ovaries by the corpus luteum. In women, this hormone is produced just before ovulation to increase the chance of getting pregnant. If you are having difficulty getting pregnant, your doctor make check your Progesterone levels near your menstrual cycle. Progesterone helps prepare the lining of the uterus (endometrium) to receive the egg if it becomes fertilized by a sperm. If the egg is not fertilized, progesterone levels drop and menstrual bleeding begins. Without sufficient progesterone levels, the lining of the uterus will begin to shed. If a woman is pregnant and has low progesterone levels this may result in miscarriage.
In the event of a pregnancy the placenta produces high levels of Progesterone. Because this, your doctor can use your Progesterone level to confirm a pregnancy. In early pregnancy, progesterone measurements may be used, along with human chorionic gonadotropin (hCG) testing, to help diagnose an ectopic or failing pregnancy. Progesterone levels may also be ordered to monitor a high-risk pregnancy to help evaluate placenta and fetal health. Decreased levels are seen in ectopic pregnancies and in miscarriages.
A form of progesterone is also given to induce bleeding in women who do not frequently have a period, which is common in women with Polycystic Ovarian Syndrome (PCOS). Extended periods of time without having a period can increase a woman’s risk for endometrial cancer.
Progesterone levels during the menstrual cycle
- Days 1-14: Less than 1 nanogram per milliliter (ng/mL) or 0.5-2.3 nanomoles per liter (nmol/L)
- Days 15-28: 2-25 ng/mL or 6.4-79.5 nmol/L
Progesterone levels during pregnancy
- 1st trimester: 10-44 ng/mL or 32.6-140 nmol/L
- 2nd trimester: 19.5-82.5 ng/mL or 62-262 nmol/L
- 3rd trimester: 65-290 ng/mL or 206.7-728 nmol/L
Progesterone levels after menopause
- Normal: Less than 1.0 ng/mL or less than 2 nmol/L
What does progesterone do?
- Helps to regulate the menstrual cycle.
- Prepares the lining of the uterus for implantation.
- Normalize zinc and copper levels
- Keeps the lining of the uterus thick which is necessary for a successful pregnancy.
- Produces a rise in temperature after ovulation, which remains until menstruation occurs.
- Creates a nutrient rich environment for the baby by increasing glycogen and arterial blood to the lining of the uterus.
- suppresses prolactin (the primary hormone of milk production), preventing lactation until birth
- Normalize blood sugar levels
- Restores proper cell oxygen levels
- Keeps the uterus from having contractions.
- Causes the cervix to thicken and create a mucous plug which prevents bacteria from entering the uterus.