FSH, or follicle stimulating hormone, is produced by our pituitary gland and stimulates the growth of follicles that contain the egg cells in our ovaries. It is the main hormone responsible for producing mature eggs in the ovaries.
FSH levels fluctuate through a woman's lifetime, indicating fertility, perimenopause and menopause. Levels change monthly to encourage the ovary follicles to release eggs to the Fallopian tubes for fertilisation.
The normal FSH range for a woman looking to conceive will fall between 5 and 25 mIU/ml. In a woman about to enter menopause, it will be 50 or higher. Women in perimenopause will be 25 or higher.
To indicate fertility, many clinics test FSH levels on day 3 of your menstrual cycle to see how hard your body is working to stimulate follicle growth. The lower the level, the better, meaning your body has worked hard to stimulate and release all mature eggs.
When determining fertility, FSH numbers can be subjective. Some doctors like to see numbers lower than 15, while others look for a number lower than 12 or 9.
Knowing your FSH levels will help you determine your ability to conceive, but factors such as age and other hormone levels also must be taken into consideration.