Polycystic Ovary Syndrome (PCOS): A condition in which cysts in the ovary interfere with normal ovulation and menstruation.

Polycystic Ovary Syndrome (PCOS) is a problem caused by having abnormal levels of certain hormones in your body. It affects 5 to 10 percent of women during childbearing years. Symptoms start as a teenager or later in life. Learning about how hormones work in your body will help you understand PCOS.

Hormones and your menstrual cycle

Your body makes hormones that affect your menstrual cycle. The pituitary gland in your brain makes lutenizing hormone (LH) and follicle-stimulating hormone (FSH). They tell the ovaries to make estrogen and progesterone (female sex hormones). The ovaries also make a little of the male sex hormone (androgen) called testosterone.

PCOS may occur when the pituitary gland makes too much lutenizing hormone. This causes your ovaries to make more testosterone. That makes it harder to have regular periods. If you don鈥檛 have regular periods, it can be harder to get pregnant. Extra testosterone in women can cause problems with hair, skin, weight and insulin levels.