Progesterone is a hormone that supports menstruation and pregnancy. It typically rises during pregnancy and while using some birth control medications. Low levels can affect menstruation and fertility.
Hormones are chemical messengers in your body that affect a range of bodily functions, from sleep-wake cycles to digestion.
Progesterone is 1 of 2 female sex hormones, the other being estrogen. Its main functions are regulating menstruation and supporting pregnancy in the female body.
Read on to learn more about progesterone’s function and typical levels.
Progesterone is produced in the corpus luteum, a temporary mass of cells that form in the ovaries following the release of an egg.
The adrenal glands and the placenta can also produce progesterone.
During the menstrual cycle
In the middle of a person’s menstrual cycle, a rise in levels of luteinizing hormone leads to ovulation.
Progesterone helps
If the egg isn’t fertilized, the corpus luteum breaks down, leading to a drop in progesterone levels. This decrease causes the endometrium (tissue lining) to break down, resulting in the beginning of a menstrual period.
During pregnancy
If an egg is fertilized, the corpus luteum doesn’t break down and continues to produce progesterone. It then stimulates blood vessels to supply the endometrium and provide nutrients to the developing embryo.
Once the placenta has formed, it becomes the primary producer of progesterone.
Levels of progesterone remain elevated throughout pregnancy, which prevent the body from producing additional eggs during the pregnancy.
Eventually, progesterone helps trigger lactation.
In males
In males, adrenal glands also produce progesterone. Its function is associated with sperm development.
A healthcare professional may want to test your progesterone levels for a number of reasons.
Some of them include:
- determining whether someone has ovulated
- evaluating underlying causes of infertility
- determining whether someone has had a miscarriage or ectopic pregnancy
- assessing people with a high risk pregnancy or who are taking progesterone during pregnancy
- narrowing down causes of atypical uterine bleeding
- diagnosing an adrenal disorder
Healthcare professionals measure progesterone levels through a blood test. It’s important to remember that levels fluctuate throughout the menstrual cycle and can vary throughout the month.
Progesterone levels are measured in nanograms per milliliter (ng/mL). The chart below lists what are considered normal levels of progesterone for an adult female during different points of the menstrual cycle and pregnancy.
| Stage | Progesterone level (ng/mL) |
|---|---|
| follicular stage of the menstrual cycle | < 0.7 |
| luteal stage of the menstrual cycle | 2 to 25 |
| first trimester of pregnancy | 10 to 44 |
| second trimester of pregnancy | 19.5 to 82.5 |
| third trimester of pregnancy | 65 to 290 |
It’s important to keep in mind that laboratory results can vary. If you’re unsure about your test results, consider speaking with a healthcare professional.
High levels of progesterone, which are naturally reached during pregnancy, typically don’t cause any negative health effects.
In fact, progesterone is present in oral contraceptives because it can trick the body into not ovulating.
Low progesterone levels can affect both menstruation and fertility. Progesterone helps promote a good environment for a fertilized egg. Low progesterone levels
Low levels of progesterone can also contribute to certain conditions, including:
- absence of menstruation
- miscarriage
- low ovarian function
What does progesterone do in HRT?
Hormone replacement therapy (HRT) can treat menopause symptoms and often includes progesterone. Progesterone in HRT can help prevent the womb lining from growing too thick.
What are the side effects of progesterone?
Side effects of progesterone medication can include fatigue, headaches, and abdominal and muscle pain.
What are the benefits of taking progesterone?
The benefits of taking progesterone include helping alleviate menopause symptoms such as hot flashes, tender breasts, and fatigue.
Progesterone is a hormone that’s vital for functions such as menstruation, pregnancy, and sperm production. It’s produced in a variety of locations, including the corpus luteum, placenta, and adrenal glands.
Progesterone levels fluctuate throughout the cycle and reach high levels during pregnancy. However, if levels get too low, it can lead to health issues, including infertility.