FSH Levels by Age - Follicle Stimulating Hormone Levels with Chart
Medically reviewed by Norbert Gleicher, MD, FACOG, FACS - Written by CHR Staff - Updated on Jul 31, 2020
It’s important to recognize that there is no one “normal” level of FSH for all women. What is normal is that the normal range changes depending on a woman’s age. As women get older, follicle stimulating hormone levels rise, until they reach a level of 40 mIU/mL or higher during menopause. This means that, for example, test results that are deemed high FSH levels for a woman in her mid-20s may be considered relatively low FSH levels for a woman in her mid-30s. The chart further down this page can help you understand what level is normal for you, based on your age.
Follicle stimulating hormone, or FSH, is a key gonadotropin secreted by the pituitary gland in both men and women. It acts on the ovaries and the testicles together with luteinizing hormone (LH), another gonadotropin that is also produced in the pituitary. Both follicle stimulating hormone and luteinizing hormone play important roles in the development of eggs in the ovaries and sperm in the testicles.
In women, both FSH and LH rise during the early part of the menstrual cycle (the follicular phase). Ovulation occurs just after they peak. The levels of both hormones remain low during the luteal phase of the cycle (until the next menstrual period). Because of this, FSH testing needs to be performed on a specific day of the menstrual cycle (day 2 or 3) and all reference values reflect FSH at this time.
Do Not Wait for FSH to Improve
CHR explains why treatment should not be postponed when FSH is high.
FSH Levels for Female Fertility
An FSH test is a blood test that measures follicle stimulating hormone to check whether levels are normal, and it is a common part of any infertility workup ordered at a reproductive endocrinology clinic. This hormone test is not done as a urine test.
The same blood sample is typically used for FSH testing and to measure several other fertility hormones. This information is then used as an indicator of the woman’s ovarian function.
A low FSH result is generally associated with better ovarian function. Higher levels are associated with diminished ovarian reserve, which makes pregnancy difficult. Most women have low FSH in their 20s, and levels increase naturally as women age. For this reason, FSH is also one of the key hormones measured in fertility lab tests online that aim to gauge a younger woman’s future fertility. These tests evaluate whether a woman may have premature ovarian aging (POA).
Interpreting Your FSH Levels: What FSH Test Result is Normal for You?
About 15 years ago, CHR's research established reference ranges for AMH and FSH levels by age. Before this development, IVF centers had been using universal “normal” ranges for AMH and FSH for everyone regardless of age. This practice hindered proper diagnosis of DOR, particularly in younger women, because the level of each of these hormones means something different depending on a woman’s age. For example, a completely normal level of FSH for a woman of 42 suggests premature ovarian aging (POA) if found in a 30-year-old. To really assess a woman's ovarian reserve and her IVF pregnancy chances, we need to look at age-specific levels. The chart below demonstrates the normal levels by age among CHR's patients. You can learn more about IVF after 40. It is also important to remember that hormonal birth control affects test results because it suppresses FSH.
FSH Level Chart by Age
As the table demonstrates, normal levels of FSH go from below 7.0 mIU/mL for someone younger than 33 to over 8.5 mIU/mL for a woman over 41. This chart is an important tool that we use to create tailored fertility treatment plans for our patients.
Baseline FSH and AMH Levels by Age
Age | FSH (On Day 3 of the Menstrual Cycle) | AMH (Any Day of the Menstrual Cycle) |
< 33 Years | < 7.0 mlU/mL | = 2.1 ng/mL |
33-37 Years | < 7.9 mIU/mL | = 1.7 ng/mL |
38-40 Years | < 8.4 mIU/mL | = 1.1 ng/mL |
= 41+ Years | < 8.5 mIU/mL | = 0.5 ng/mL |
Normal FSH levels by age, measured on day 3 of the menstrual cycle. The normal level of this hormone naturally increases as a woman gets older.
"CHR developed and uses an age-based AMH and FSH levels chart, which is more accurate at predicting pregnancy chances."
Many fertility centers, unfortunately, still use universal cut-off values for all ages. This can mean that a fertility healthcare provider may give a younger woman with POA and higher FSH for her age (but within normal range based on a universal “normal” value) an inappropriate fertility treatment or misdiagnose her with “unexplained infertility.”
When a patient has high follicle stimulating hormone, some of these fertility centers also refuse to provide treatment, irrespective of patient age and other factors. Or centers may push women to egg donation (prematurely, in our opinion). This approach may ensure higher pregnancy success rates at such centers (because they are rejecting women with lower chances of pregnancy). But it leaves women with elevated FSH (and/or low AMH) ) abandoned, without access to fertility treatment with their own eggs that can be quite successful if done correctly.
CHR does not use such arbitrary cut-off values. We look at follicle stimulating hormone range in the context of a woman’s age and other factors. This way, our physicians are able to individualize fertility treatments for each woman’s level of ovarian function. We also know that with high FSH time is of the essence. We stayed open during COVID-19 closures to ensure that women could immediately initiate fertility treatment in these cases. This is why we have so many patients with stories of successful pregnancy with their own eggs with treatments like tailored in vitro fertilization!
FSH is Not a Single Best Measure of Fertility
What makes the “universal FSH cut-off” approach even more problematic is the fact that the most up-to-date medical literature suggests that follicle stimulating hormone is not as specific as it was once thought. A number of papers published by CHR's physicians (such as this one) suggest that AMH is essential in assessing ovarian reserve and pregnancy chances with IVF.1 This makes sense because AMH level reflects the smaller follicles, which represent a majority of a woman's ovarian reserve. Given this, IVF treatment decisions based on follicle stimulating hormone alone appear outdated.
While tests to check levels of FSH and AMH are important in assessing ovarian reserve, both have limitations. Neither result can, indeed, categorically determine whether a woman can or cannot conceive, unless she has very high levels of follicle stimulating hormone. Therefore, placing too much emphasis on the levels of these hormones can be misleading. It can also be harmful, as some physicians make patients wait for lower follicle stimulating hormone levels to magically appear in the next blood test before starting an IVF cycle--a practice that wastes precious time and makes no physiological sense.
FSH Levels and Other Health Conditions
FSH testing may be recommended in a number of other situations, in both adults and children, because it may be associated with a suspected medical condition. For example, an individual who has a pituitary disorder may not produce sufficient levels of FSH. People with thyroid disease, specifically hypothyroidism, also have low levels of FSH.2 Even though low FSH is associated with better ovarian function, abnormally low levels or a hormone imbalance can be causes of infertility.
Women with PCOS, or polycystic ovary syndrome, tend to have elevated levels of AMH, while their FSH is low in comparison. This affects how the two hormones interact to facilitate female reproduction. With PCOS, a course of the medication clomiphene is sometimes prescribed to induce the ovarian follicles to release eggs. This reproductive medicine has been FDA-approved and utilized in reproductive endocrinology for over 50 years,3 though at CHR we use it judiciously only for certain treatments and patients. FSH is also the main hormone used to diagnose premature ovarian failure (POF), when it is elevated above the 40 mIU/mL threshold before the normal age for menopause. During perimenopause, FSH levels rise, and then remain high in menopause.
High levels of FSH are also seen in some genetic disorders. Women with Turner syndrome and men with Klinefelter syndrome have elevated FSH even at a very young age.45
In children, higher than normal FSH may be related with precocious puberty, and a pediatrician may order an FSH test if a girl or boy has early symptoms of puberty.
Sources
1. Gleicher, N. Anti-Müllerian hormone (AMH) defines, independent of age, low versus good live-birth chances in women with severely diminished ovarian reserve. Fertility and Sterility. Link. Published December 1, 2010. Accessed August 18, 2020.
2. Weghofer A, Himaya E, Kushnir VA, Barad DH, Gleicher N. The impact of thyroid function and thyroid autoimmunity on embryo quality in women with low functional ovarian reserve: a case-control study. Reproductive biology and endocrinology : RB&E. Link. Published May 15, 2015. Accessed August 18, 2020.
3. Clomid. In: Drugs@FDA Online. [Accessed August 18, 2020]. Link.
4. Turner syndrome - Genetics Home Reference - NIH. U.S. National Library of Medicine. Link. Published August 17, 2020. Accessed August 18, 2020.
5. Klinefelter syndrome - Genetics Home Reference - NIH. U.S. National Library of Medicine. Link. Published August 17, 2020. Accessed August 18, 2020.
Norbert Gleicher, MD, FACOG, FACS
Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.