Interpreting Your FSH Levels
FSH is a hormone released by the pituitary gland, located on the underside of the brain. The FSH test is a common part of any infertility workup, and measures the level of FSH in the blood to gauge the ovarian function.
A few years ago, CHR's research established age-specific levels of FSH and AMH . Any FSH level means different things if found at different ages. For example, a normal FSH level for a woman at 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, one really needs to look at age-specific AMH and FSH levels. The AMH and FSH levels chart below demonstrates age-specific AMH and FSH levels for CHR's patients.
AMH and FSH Levels: Chart by Age
What is a normal FSH level? The answer to this common question needs to be based on the woman’s age, as FSH levels naturally rise as women get older. The table below shows normal FSH levels (along with AMH levels) by female age. As the table demonstrates, normal FSH levels go from below 7.0 mIU/mL for someone younger than 33 to over 8.5 mIU/mL for a woman over 41.
Age Specific Baseline FSH and AMH Levels
|< 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|
"CHR developed and uses an age-based AMH and FSH scale, which is more accurate at predicting pregnancy chances."Dr. Norbert Gleicher
Many fertility centers, unfortunately, still use universal cut-off values for FSH (and AMH). When a patient has high FSH, some of these centers simply refuse to provide treatment, irrespective of patient age and other factors, or push women to egg donation (prematurely, in our opinion). This approach may ensure higher pregnancy rates at such centers (because they reject women with lower chances of pregnancy), but it leaves women with elevated FSH (and/or low AMH) abandoned. CHR, therefore, does not have such arbitrary cut-off values.
Below, we’ve provided a normal FSH levels by age chart, which shows the age-specific normal level of FSH along with AMH, as they change over a woman’s reproductive lifetime.
Normal FSH Levels by Age
What makes the “universal FSH cut-off” approach even more problematic is the fact that the most up-to-date medical literature suggests that FSH is not as specific as it was once thought. A number of papers published by CHR's physicians suggest that AMH is actually more specific than FSH in assessing ovarian reserve and pregnancy chances with IVF. Better AMH specificity makes sense because AMH reflects the smaller follicles,follicles, which represent a majority of a woman's ovarian reserve. (The figure above demonstrates that ranges are narrower for AMH than FSH, suggesting that AMH is more precise in reflecting ovarian reserve.) Given the superiority of AMH, IVF treatment decisions, based on FSH levels alone, appears outdated.
While tests to check AMH and FSH levels are important in assessing ovarian reserve, both have limitations. Neither FSH nor AMH can, indeed, categorically determine whether a woman can or cannot conceive, unless she has very high FSH levels. Women can get pregnant with IVF even when AMH is completely undetectable, as over 50 pregnancies established so far at CHR in women with undetectable AMH levels clearly demonstrate. Therefore, placing too much emphasis on high FSH and low AMH can be misleading.
Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned reproductive endocrinologist, 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.
Last Updated: October 8, 2018