FSH (Follicle Stimulating Hormone) in Serum or Plasma

What Is Follicle-Stimulating Hormone (FSH)?

FSH is a hormone produced by the pituitary gland, which is a small gland at the base of your brain. It works with another hormone, luteinizing hormone (LH), to regulate the menstrual cycle in women and sperm production in men. FSH helps stimulate the growth of follicles (small fluid-filled sacs containing immature eggs) in the ovaries and the production of sperm in the testes.

Why Might You Need This Test?

Doctors may order an FSH test to check for hormonal imbalances, evaluate fertility issues, diagnose conditions like polycystic ovary syndrome (PCOS), or assess reproductive health in both men and women. It can also help monitor conditions like premature ovarian insufficiency or hypogonadism.

When Is an FSH Test Performed?

FSH testing is often done during specific phases of the menstrual cycle (e.g., mid-cycle) or at certain times of the day to get the most accurate results. For men, it may be checked at any time since FSH levels don’t fluctuate as much.

What Does a High or Low FSH Level Mean?

High FSH levels may indicate problems with the ovaries or testes, such as reduced egg or sperm production, early menopause, or certain genetic conditions. Low FSH levels could suggest pituitary gland issues or other hormonal imbalances.