Evidence-informed guide Glossary

Follicle-stimulating hormone (FSH)

FSH: a pituitary hormone that drives ovarian follicle growth, and how it relates to ovulation and PCOS assessment.

by Pasukan Editorial Panduan PCOS Last reviewed: 5 May 2026

Only a doctor can diagnose PCOS. This article is for education, not a substitute for medical advice.

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Why it matters for PCOS
FAQ
Sources

FSH (follicle-stimulating hormone) is a pituitary hormone that drives ovarian follicles to grow.

Why it matters for PCOS

FSH is released by the pituitary gland in the brain and signals follicles in the ovary to grow, helping an egg mature each menstrual cycle. It works in tandem with LH (luteinising hormone), and the balance between the two governs ovulation. In some women with PCOS the ratio of LH to FSH tends to run high, which can contribute to irregular ovulation.

An FSH result is interpreted in context, not on its own. It is read alongside LH, oestradiol, symptoms, and when in the cycle the sample was taken. Your doctor is best placed to explain what your result means.

This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.

FAQ

Frequently Asked Questions

What is FSH?

FSH is follicle-stimulating hormone, released by the pituitary gland. It signals follicles in the ovary to grow, which helps an egg mature each cycle.

How does FSH relate to PCOS?

In some women with PCOS the ratio of LH to FSH tends to run high. Even so, FSH is not read on its own and is interpreted alongside LH, oestradiol, and when in the cycle the sample was taken.

When is FSH usually tested?

Hormone tests like FSH are often taken in the early part of the menstrual cycle, because timing affects interpretation. Your doctor will advise the right timing for your situation.

Sources

Teede HJ et al.. International evidence-based guideline for the assessment and management of polycystic ovary syndrome 2023. Fertility and Sterility / Endocrine Society. 2023.PubMed