Different Estradiol Level's Impact on Appetite Regulation, Food Intake, and Concentrations of Leptin, Glucagon-Like Peptide-1, and High-Sensitivity C-Reactive Protein During a Long Agonist IVF Protocol

Background: Do different hormonal phases affect appetite regulation, food intake, and concentrations of leptin, glucagon-like peptide-1 (GLP-1), and high-sensitivity C-reactive protein (hs-CRP) during a long agonist in vitro fertilization (IVF) protocol? Does the IVF stimulation induce metabolic changes, which might impact maternal health? Methods: Fifty-four infertile women were encountered thrice, the first of which was at the beginning of their period (low estradiol). The other two were during a gonadotrophin-releasing hormone (GnRH) analog downregulation (low estradiol) and at the end of a follicle-stimulating hormone (FSH) stimulation (high estradiol). The first visit was the reference; the women served as their controls. The concentrations of leptin, GLP-1, and hs-CRP were assessed from plasma. Dietary intake was assessed using food records (FRs) three days before each visit. In addition, weight, height, body mass index (BMI), and plasma levels of estradiol, glucose, HbA1c, insulin, and lipids were monitored. Twenty-six of the subjects also had a postprandial test, in which the blood samples were taken at five time points at every three visits. They also filled visual analog scales to exhibit satiety and appetite. Twenty-eight of the subjects had only fasting blood samples. Results: During the stimulation protocol, leptin concentrations elevated (P<0.001), and energy intake decreased (P=0.03) while estradiol levels increased (P<0.001). GLP-1 levels unchanged (P=0.75) and hs-CRP (P=0.03) concentrations diminished while estradiol levels increased. Conclusions: No increased food intake or weight gain occurred during the stimulation protocol; thus, leptin may protect from overeating during high estradiol levels, and leptin resistance may not occur during a short follow-up. Also, a favorable anti-inflammatory effect was detected. During this study, no harmful metabolic effects occurred, which might have a disproportionate impact on maternal health. Trial registration: Not applicable. This study is a clinical study without intervention.