Normal levels of FSH for people assigned female at birth can vary by age and the phase of the menstrual cycle. For example, in the follicular phase, it can range from 1 to 9 international units per liter (IU/L).
Hormonal disruption and other factors can lead to high or low levels. However, many factors can affect FSH levels, including a person’s weight and various health issues.
Follicle-stimulating hormone (FSH) plays an integral role in reproductive processes. Doctors can test FSH levels to assess fertility, among other things.
In people assigned female at birth, FSH helps mature the ovarian follicles that release eggs, called ova. Without the release of FSH, the reproductive cycle cannot continue, as the ovaries will not release an egg.
People assigned male at birth use FSH to support the growth and development of sperm.
Doctors can check FSH levels using a blood test to assess fertility or see if a person is going through menopause. They typically do this alongside tests for other sex hormones, such as testosterone or estrogen.
This article explores what FSH levels are and how FSH tests relate to menopause and fertility.
Sex and gender exist on spectrums. For the purposes of this article, we use “male” and “female” to refer to a person’s sex assigned at birth. Learn more.
Doctors order blood tests to measure FSH levels in terms of international units per liter (IU/L).
Normal FSH ranges in females
A person’s FSH level will change throughout their lifetime. Below is one set of guideline ranges for FSH levels for females at different life stages.
These ranges may vary depending on what exact tests a laboratory runs.
| Normal FSH levels | |
| Before puberty | 0 to 4 IU/L |
| During puberty | 0.3 to 10 IU/L |
| While still menstruating | 4.7 to 21.5 IU/L |
| After menopause | 25.8 to 134.8 IU/L |
If a female has an FSH level of 30 IU/L or higher and has not had a period for a year, they have probably reached menopause.
However, doctors do not require tests to diagnose menopause. They can often diagnose menopause by assessing a person’s medical history and symptoms.
A menstruating person’s typical FSH levels will vary throughout the stages of the menstrual cycle.
| Menstrual cycle stage | Normal FSH levels |
| Follicular | 1 to 9 IU/L |
| Ovulatory phase | 6 to 26 IU/L |
| Luteal | 1–9 IU/L |
During the early stages of pregnancy, 26 to 30 days after ovulation, a person’s FSH levels drop to around 0.1 IU/L.
Normal FSH ranges in males
A person’s FSH levels will change throughout the course of their life. Below are one United States medical institution’s typical FSH ranges for males. Other institutions may have different ranges.
| Age | FSH range |
| Before puberty | 0 to 5 IU/L |
| During puberty | 0.3 to 10 IU/L |
| Adulthood | 1.5 to 12.4 IU/L |
These ranges can vary between laboratories and studies. For example, an older
Further tests
When testing for fertility in females, a doctor may also ask a person to track their temperature, as this can rise during ovulation. Similarly, they may order imaging scans to check the fallopian tubes. The egg cannot travel to the uterus for implantation if the tubes are blocked.
If a person is experiencing irregular periods around the age of menopause, doctors may test for other hormone levels, including thyroid-stimulating hormone and prolactin, to help guide diagnosis.
In females, elevated levels may be a sign of menopause, which can cause symptoms including:
A rare condition called ovarian hyperstimulation syndrome (OHSS) can cause high FSH levels in females. It is thought to be related to cystic enlargement of the ovaries with fluid leakage from the ovaries. OHSS is rare in the absence of fertility treatments.
Doctors will regularly monitor people undergoing these treatments for any signs of OHSS.
Symptoms of OHSS include enlarged ovaries and the accumulation of fluid in the abdomen, leading to pelvic pain.
Health conditions with links to high levels of FSH
Besides menopause and OHSS, in females, high FSH level has links to:
- polycystic ovary syndrome (PCOS)
- primary ovarian insufficiency (POI)
- ovarian tumor
- thyroid or adrenal gland conditions
- improper development of the ovaries
- Turner syndrome, a chromosomal disorder
In males, high FSH has links to:
- mumps
- a germ cell tumor
- Klinefelter syndrome, a chromosomal disease
In both females and males, high FSH level also shares links with radiation therapy, chemotherapy, and certain autoimmune diseases.
In children, low levels of FSH may be a sign of delayed puberty. Symptoms of low FSH levels include:
- limited sperm production
- infertility
- delays in sexual development
Low FSH levels in female and male adults may indicate an issue with the pituitary gland or hypothalamus, which can affect the production of the hormone.
Low FSH in females also shares links with being underweight or extreme exercise.
Doctors often order the FSH test as part of a range of tests. There are a number of reasons to carry out the FSH test, including:
- Menopause testing: If a person’s menstrual cycle has become irregular or they have not had a period at all, a doctor may order the test. If FSH levels are high, it could indicate menopause.
- Female fertility testing: If a person is not ovulating, their FSH levels might be high or low, depending on the cause.
- Male fertility testing: FSH stimulates the growth of sperm cells. If a person’s FSH levels are high, it can mean their testicles are not functioning properly.
In addition to testing for fertility and menopause, doctors may order an FSH test to look for a pituitary disorder or determine if a child is entering puberty too early or too late.
The
An FSH test usually consists of a simple blood test. A small sample of blood is necessary, and the risks are minimal. Afterward, a person can generally return to their everyday activities.
A doctor will not use the FSH test alone to determine if a person is going through menopause or identify reasons for infertility.
One downfall of hormone testing is that a person’s hormones fluctuate over hours and days. So, taking a blood sample and testing it for hormones provides only a “snapshot” of their levels. As a result, many doctors will ask people to take an FSH test on day three of their cycle when testing for fertility.
A diagnosis based on FSH levels alone might be inaccurate, particularly in females. Males typically have steadier hormone levels.
Certain medications can affect FSH levels. To prevent false readings, it is important for people to tell their doctor about any medications or herbal supplements they are taking.
Medications that decrease FSH levels include:
- hormone replacement therapies
- oral contraceptives
- phenothiazines
FSH tests can help a doctor evaluate fertility or menopause status.
A doctor may recommend taking several blood samples from a menstruating person throughout their menstrual cycle to see if their FSH levels are consistently high, low, or normal.
However, most people going through menopause will not require FSH testing.
In females
- irregular periods
- hot flashes
- mood changes
- difficulty sleeping
- vaginal dryness
For
FSH plays an essential role in the reproductive health of females and males. In females, high FSH levels can indicate menopause, PCOS, or other health conditions. In males, high FSH shares links with tumors and mumps.
If FSH levels are too high in children, it can indicate a delay in puberty. In adults, low FSH can signal an issue with the pituitary gland or hypothalamus, affecting the hormone’s production.
