Effect of the Glycemic Index of Diet on Metabolic and Reproductive Parameters in Overweight and Obese Infertile Women

Overview

Infertility has been currently recognized as a disorder related to obesity. Among several metabolic changes associated with obesity, insulin resistance appears to be linked to hormonal disorders that affect reproductive system. Leptin and ghrelin are hormones involved in energy balance regulation and are also associated with reproductive system regulation, but its relationship with infertility is scarce. The aim of this study is to determine the effect of a hypocaloric diet with different glycemic indexes on ghrelin and leptin levels, hormonal, metabolic and reproductive parameters in infertile overweight or obese women candidates to in vitro fertilization. The patients who meet the inclusion criteria and accept to participate in the study, will be allocated in one of the following groups: Hypocaloric Low Glycemic Index diet group; Hypocaloric Conventional diet group or Control group (maintenance of usual diet) and follow the study protocol for 12 week. Immediately after the end of the diet protocol, the patients will be submitted to the in vitro fertilization treatment.

Infertility has been currently recognized as a disorder related to obesity. Among several metabolic changes associated with obesity, insulin resistance appears to be linked to hormonal disorders that affect reproductive system. Leptin and ghrelin are hormones involved in energy balance regulation and are also associated with reproductive system regulation, but its relationship with infertility is scarce. The aim of this study is to determine the effect of a hypocaloric diet with different glycemic indexes on ghrelin and leptin levels, hormonal, metabolic and reproductive parameters in infertile overweight or obese women candidates to in vitro fertilization. Infertile women with grade I and II obesity, or pre-obesity with increased waist circumference will be recruited. Patients will be assigned to Hypocaloric Low Glycemic Index diet group; Hypocaloric Conventional diet group or Control group (maintenance of usual diet), and will follow the protocol for 12 weeks. The two intervention diets will be similar in terms of caloric intake and macronutrient distribution and different in terms of carbohydrates quality (index and glycemic load). Immediately after the end of the diet protocol, the patients will be submitted to the in vitro fertilization treatment. Before and after the intervention anthropometric measurements (weight, height, body mass index, waist and hip circumference) and body composition (body fat percentage determined by the measurement of seven skinfolds) will be evaluated as well as biochemical parameters: leptin, acylated ghrelin, glucose, insulin, serum lipids (total cholesterol and lipoproteins, and triglycerides), sex hormones - follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, prolactin, testosterone and sex hormone binding globulin (SHBG). Primary outcome: clinical pregnancy rate. Secondary outcomes: HOMA-IR (Homeostasis Model Assessment), acylated ghrelin and leptin levels, body fat percentage, number of oocytes retrieved, percentage of fertilized oocytes and embryo quality.