Normally a woman ovulates when follicle grows and releases a mature egg. But when the growth of follicle is arrested, it builds up in the ovaries itself to form small cysts called polycystic ovaries. Women with PCOS generally have insulin resistance (can be hereditary or due to certain lifestyle factors) in which the body does not respond quickly to insulin. As a result, blood levels of insulin rise as the body attempts to maintain normal glucose levels. Elevated blood insulin affects reproductive hormones, resulting in increased production of androgens by the ovary. Androgens are “male” hormones (testosterone), which are normally produced in minor quantities in women. If produced in excess, it results in anovulation and an increase in Luteinizing Hormone (LH) / Follicle-Stimulating Hormone (FSH) ratio in women. This complex positive feedback of insulin resistance and hyperandrogenism arrests the follicles from growing at an early stage and causes them to build up in the ovaries to form small cysts called polycystic ovaries.