What is an ovarian cyst? Ovarian cysts are fluid filled sacs that form on or in the ovaries. Ovaries are the female reproductive glands that produce ova (singular_ovum or egg cell). They are present in pair. Each female has two ovaries, one on each side of the uterus.   Ovaries produce follicles during the menstrual cycle. The production of follicles, their growth and the maturation of single ovum are all events regulated by the secretion of the female sex hormones, estrogen and progesterone. Under the influence of these hormones, the release of ovum occurs which is termed as ovulation. It takes place on the 14th day of the cycle, if the period cycle is of regular nature,i.e 28 days.    Normal menstrual cycle may be anywhere from 21-40 days. The number of days vary from woman to woman.  Ovarian cysts are usually harmless and there's no need to worry about unless you experience any symptom. Many women have ovarian cysts during their reproductive age due to ...