Still, it's important to be watchful of any symptoms or changes in your body and to know which symptoms are serious. Causes Your ovaries normally grow cystlike structures called follicles each month. Sometimes a normal monthly follicle just keeps growing. When that happens, it becomes known as a functional cyst. This means it started during the normal function of your menstrual cycle.
Ovulation initiates a complex chain reaction.
When everything goes according to plan, your egg is released and begins its journey down the fallopian tube in search of fertilization. A follicular cyst begins when LH doesn't surge and the chain reaction doesn't start. The result is a follicle that doesn't rupture or release its egg. Instead, it grows and grows until it becomes a cyst. Follicular cysts are usually harmless, rarely cause pain and often disappear on their own within two or three menstrual cycles.