Obesity and pathophysiology of reproduction

Android obesity leads to development of several chronic diseases like type 2 diabetes, cardiovascular disease, hyperlipidemia, irregular menstrual cycle, infertility and miscarriage. Disturbance circulating metabolic hormones like leptin and insulin and sex hormones are main cause of these abnormalities. Overfeeding causes hyperinsulinemia and insulin resistance which in turn causes excessive androgen production. During puberty, critical amount of fat and high insulin decreases two binding proteins, SHBG and IGF binding protein that increases circulating free sex steroids. These free sex steroids are responsible for sexual maturation at puberty. Insulin causes androgen production but long-term exposure to insulin causes polycystic changes in ovary. Increased GnRH together with high LH pulse frequency and decreased negative feedback to LH is also reported. Hyperinsulinemia and high LH are responsible for high androgen production from the ovary but aromatase activity in not that much upregulated. That leads to high circulating androgen and anovulation in PCOS.