In polycystic ovarian syndrome, also known as Stein Leventhal Syndrome, a hereditary hormone imbalance causes multiple cysts to develop on the ovaries. These cysts can cause pain, irregular and painful periods, weight gain, excess body hair and infertility, or they can cause no symptoms at all. Four percent of women have PCOS.
Polycystic ovarian syndrome is different from ovarian cysts, which rarely cause infertility.
Three hormones are produced in the ovaries: estrogen, androgen and progesterone. Two more - follicle stimulating hormone (FSH) and luteinizing hormone (LH) - are produced in the pituitary gland in the brain. The hormones produced in the brain regulate the production of the hormones produced in the ovaries.
The exact causes of the hormone imbalance that leads to PCOS is unclear. Production of FSH and LH is irregular, so problems develop with the other three hormones as well. Too much androgen is produced, too little progesterone, and the same amount of estrogen. As a result, the follicle, the fluid filled sac that develops around the egg before it ovulates, never develops. Instead, it turns into a cyst on the ovary. It is the abnormal progesterone level that prevents the follicle from developing, but the progesterone is influenced by all of the other hormones.
