Obesity, we can see from the appearance at a glance, but many people do not really realize the harm of obesity, now we will go further to recognize the harm of obesity as a disease, especially on the impact of reproductive function. First, the definition of obesity Weight measurement method: (1) body mass index (BMI): simple, practical, the most commonly used in clinical practice. Body mass index (BMI) = weight (kg) / height 2 (m2). Second, the classification of obesity 1, simple obesity, also known as primary obesity, is the most common type of obesity, accounting for about 95% of the obese population; 2, secondary obesity is caused by endocrine diseases or metabolic disorders caused by a class of obesity, common diseases are: cortisolism; hypothyroidism; polycystic ovary syndrome (PCOS), PCOS patients, obese ≥ 50%; 3, Pharmacologic obesity For example, glucocorticoid drugs, phenothiazines for the treatment of psychosis. The effect of obesity on reproductive function The maintenance of normal menstruation and reproductive function requires a critical mass of fat stores, and the effect of body weight on reproductive function is inverted U-shape, i.e., fertility is reduced when body weight is extremely high and extremely low. Obesity has a significant impact on fertility and can lead to menstrual disorders, anovulation, infertility, miscarriage, and poor pregnancy outcomes. Obese women have lower pregnancy rates in both natural and infertility treatment cycles, as well as lower rates of ovulation induction and IVF success compared to normal weight women. The following is a study of patients with PCOS: It is now believed that obese patients can develop insulin resistance, hyperandrogenemia and leptin resistance, which in turn can affect reproductive function. Insulin resistance, hyperinsulinemia and hyperandrogenemia Insulin resistance and hyperinsulinemia can cause hyperandrogenemia through certain mechanisms. Excess androgens cause an increase in LH secretion and a decrease in follicle stimulating hormone (FSH) secretion by regulating the release of gonadotropin-releasing hormone (GnRH). Elevated LH further stimulates the ovaries to produce androgens. Elevated androgen concentration and decreased FSH concentration in the ovary impede normal granulosa cell differentiation, and estrogen deficiency in the ovary leads to impaired follicular maturation, chronic anovulation, and subsequent infertility. Second, high leptin and leptin resistance Leptin is mainly secreted by adipocytes, and its level is positively correlated with BMI and positively correlated with body fat content, which means that leptin resistance exists in obese women. Physiological concentrations of FSH are not sufficient to promote follicular development and ovulation. Some factors produced by dominant follicles, such as IGF-1, can enhance the effect of FSH and gain selective priority for development in a large number of follicles. And leptin can hinder the interaction between these factors, inhibit follicular development, ovulation, resulting in reduced fertility in obese women. High levels of leptin inhibit the production of androstenedione by follicular membrane cells and act on the granulosa cells to prevent androstenedione aromatization, a combination that prevents the dominant follicle from producing the appropriate amount of estradiol, which is insufficient to maintain the fertility cycle and prepare the lining for implantation, leading to infertility. Take Action on the Benefits of Weight Loss The latest U.S. Guidelines for the Management of Overweight and Obesity in Adults state that while most studies have suggested that the goal for weight loss is 5% to 10%, in fact, clinical benefits can be achieved with a weight loss of 2% to 5%. Weight loss is the etiologic treatment for hormonal imbalance in obese women. A small reduction in body weight can reduce centrally distributed fat, improve insulin sensitivity, and lower plasma insulin levels, thereby improving fertility in infertile women. Therefore, weight loss should be the treatment of choice for obese infertile women.