FSH (Follicle Stimulating Hormone)

FSH (Follicle Stimulating Hormone) is a hormone, released from the anterior pituitary gland. It is a gonadotropin, stimulating the ovary to produce hormones and ovulate. 

FSH causes an ovarian follicle to develop and drives the pre-ovulatory rise in estrogen.

There is spike of FSH coincidental with the LH surge. These lead to ovulation within a few hours.

Elevations found in:

  • Ovulation
  • Ovarian failure
  • Testicular Feminization Syndrome

Decreases found in:

  • Polycystic Ovary Syndrome (PCO, Stein-Levinthal Syndrome)
  • Amenorrhea-Galactorrhea Syndrome
  • Pituitary failure

Normal Values*

Men 4-25 mIU/ml


4-30 mIU/ml
2 x baseline
40-250 mIU/ml

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.

FSH levels in one cycle


Gynecology and Obstetrics CD-ROM
Volumes 1-6
2004 Edition
Lippincott Williams & Wilkins
Copyright 2004
All Rights Reserved