Hormonal Changes Associated with Reproduction in Females with Prediabetes in Their Reproductive Age in Durban, South Africa

Introduction: Prediabetes represents an early stage of metabolic dysfunction characterised by insulin resistance and mild hyperglycaemia, yet its impact on female reproductive hormones remains poorly understood. Early hormonal disturbances may contribute to menstrual irregularities, impaired fertility, and progression to long-term reproductive dysfunction. This study investigated changes in reproductive hormone concentrations in females with prediabetes in their reproductive age in Durban, South Africa, with comparisons to non-diabetic and type 2 diabetic (T2DM) women. Methodology: A total of 135 females in their reproductive age were recruited and stratified into non-diabetic (n = 45), prediabetic (n = 45), and T2DM (n = 45) groups based on ADA diagnostic criteria. Blood samples were collected between days 2 and 5 of the menstrual cycle, and plasma levels of fasting glucose, HbA1c, insulin, estradiol, testosterone, progesterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured using ELISA assays. Data were analysed using one way ANOVA with a p < 0.05 considered as statistically significant. Results: Fasting glucose, HbA1c, and insulin increased progressively from the non-diabetic to the T2DM group (p < 0.0001), confirming worsening glycaemic control. Estradiol levels showed a significant decline across groups, with prediabetic women exhibiting significantly lower levels than controls but higher than T2DM (p < 0.0001). Testosterone significantly increased in prediabetes compared to non-diabetic women but significantly decreased in T2DM (p < 0.0001). Progesterone showed no significant differences between non-diabetic and prediabetic groups but declined slightly in T2DM. LH and FSH levels significantly increased from the non-diabetic, prediabetic to T2DM (p < 0.0001), suggesting early disruption of ovarian–pituitary feedback. Conclusion: The findings suggest that reproductive endocrine changes begin during the prediabetic stage, highlighting the importance of early metabolic screening to preserve reproductive health. Longitudinal studies are needed to clarify casual pathways and determine whether targeted metabolic interventions can restore hormonal balances and improve reproductive outcomes.