Follicle-Stimulating Hormone (FSH)

Follicle-stimulating hormone (FSH) is a hormone your pituitary gland makes and releases that plays a role in sexual development and reproduction. It affects the function of ovaries and testicles.

It is produced by the pituitary gland and works closely with luteinizing hormone (LH).

Functions of FSH

In Females:

• Stimulates ovarian follicles: FSH promotes the growth of follicles in the ovaries, which contain immature eggs.
• Regulates the menstrual cycle: It helps prepare the eggs for ovulation.
• Triggers estrogen production: As follicles grow, they release estrogen, which is essential for reproductive health.

Normal FSH levels in females

In general, normal FSH levels for females are:

• Before puberty: 0 to 4.0 mIU/mL.
• During puberty: 0.3 to 10.0 mIU/mL.
• After puberty: 4.7 to 21.5 mIU/mL.
• After menopause: 25.8 to 134.8 mIU/mL.

In Males:

• Supports sperm production: FSH acts on the testes to stimulate the production and maturation of sperm.
• Works with LH: Together, they regulate testosterone levels and spermatogenesis.

Normal FSH levels for males

In general, normal FSH levels for males are:

• Before puberty: 0 to 5.0 milli-international units per milliliter (mIU/mL).
• During puberty: 0.3 to 10.0 mIU/mL.
• Adult: 1.5 to 12.4 mIU/mL.

In Children:

• FSH levels are low until puberty, when they rise to initiate sexual development:
  • In girls, it stimulates estrogen production.
  • In boys, it promotes testosterone production and sperm development.

FSH Blood Test: Uses

• Infertility diagnosis: Helps identify causes of infertility in both men and women.
• Menstrual irregularities: Assesses reasons for missed or irregular periods.
• Menopause assessment: Elevated FSH levels can indicate perimenopause or menopause.
• Puberty disorders: Evaluates early or delayed puberty in children.

FSH Levels: Interpretation

• High FSH:
  • May indicate ovarian failure, menopause, or testicular dysfunction.
• Low FSH:
  • Could suggest pituitary gland issues or hypothalamic dysfunction.

References

[1] Follicle-Stimulating Hormone (FSH): What It Is & Function

[2] Follicle-Stimulating Hormone (FSH) Levels Test – MedlinePlus