The effect of sleeve gastrectomy, a bariatric surgical procedure for the treatment of morbid obesity, on women's reproductive health and fertility

Obesity is a disorder characterized by excessive accumulation of body fat, which negatively impacts health and is widely regarded as a disease by many scientists. Individuals with a body mass index (BMI) over 30 kg/m² are considered obese, while those with a BMI between 25-30 kg/m² are categorized as pre-obese or overweight. Approximately 15% of the global population is classified as obese, with rates of 16% in men and 26% in women in our country. Obesity indirectly contributes to the development of preventable non-communicable diseases such as heart attacks, strokes, diabetes, and cancer, leading to the deaths of approximately 120 million people annually worldwide. Many more individuals live with comorbidities caused by obesity. Although various methods aimed at creating a calorie deficit are used for obesity treatment, sleeve gastrectomy has become the most widely accepted standard surgical procedure in recent years. However, it must be noted that the treatment requires lifelong lifestyle changes. While it is known that obesity is associated with pathologies affecting many systems, it is widely accepted, particularly in women, that it contributes to infertility through its effects on endocrine metabolism. Research into its etiology is ongoing. Obese women frequently experience menstrual irregularities, anovulation, polycystic ovary syndrome (PCOS), difficulties in conceiving, spontaneous miscarriages, and pregnancy complications. For this reason, obesity treatment should be included in the treatment plans for female infertility. The endocrine regulation of female fertility is controlled by hormones synthesized in the hypothalamic-pituitary-ovarian (HPO) axis. Gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus, while follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are secreted by the pituitary gland. Estrogen and testosterone are released from the ovaries. The HPO axis maintains the positive feedback mechanism between estrogen and LH, thereby ensuring ovulation and implantation in women. In this study, we aimed to investigate the effects of obesity on female infertility and the potential therapeutic mechanisms for infertility by analyzing hormone levels from blood samples taken preoperatively, at three months postoperatively, and six months postoperatively in obese women who underwent sleeve gastrectomy without primary pathology in the HPO axis. In women aged 18-45 years without primary infertility pathologies who underwent sleeve gastrectomy, we observed a significant increase in FSH, LH and estradiol levels. This study suggests that one of the potential etiologies of female infertility is obesity and that sleeve gastrectomy could be incorporated into the treatment plans for infertile women with obesity.