FSH Levels by Age (UK Guide )

Follicle-Stimulating Hormone (FSH) is one of the most commonly used fertility blood tests. It helps assess ovarian function and indicates how hard the brain is working to stimulate egg development. Although FSH is only one marker, it can provide useful context when combined with AMH and ultrasound findings. --- What FSH Measures FSH measures: How much stimulation your ovaries need to develop eggs Ovarian responsiveness How close the body may be to reduced ovarian reserve High FSH usually means the ovaries require more effort to produce mature follicles. --- Typical FSH Ranges by Age (Day 2–3 Test) These ranges vary between clinics, but typical UK reference values look like: | Age | Typical FSH (IU/L) | |-----|-------------------| | 25–30 | 4–8 | | 30–35 | 6–10 | | 35–40 | 7–12 | | 40–45 | 10–20 | | 45+ | 15–25+ | Patterns to understand: FSH naturally rises with age A single high FSH reading does not confirm infertility FSH fluctuates cycle-to-cycle, unlike AMH which is relatively stable For more on AMH testing, see our AMH Test Guide. --- High FSH and Fertility High FSH can indicate: Reduced ovarian reserve Lower chance of a strong response to medication Potential need for alternative stimulation approaches But: Pregnancy is still possible with high FSH Egg quality does not correlate directly with FSH Clinics vary in how they approach treatment If you have high FSH, see our gui