How are Cortisol and fertility related?

Cortisol, the primary stress hormone, and fertility are closely linked via the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes. Chronically elevated cortisol – due to persistent stress, poor sleep, or certain medical conditions – can suppress GnRH (gonadotropin-releasing hormone) secretion, reducing LH and FSH levels. In women, this may disrupt ovulation (irregular cycles, anovulation); in men, it can impair spermatogenesis. High cortisol may also interfere with embryo implantation. Conversely, a baseline level of cortisol is necessary for normal ovarian function. Evidence comes mainly from observational studies and animal models; robust human RCTs are lacking. Genetic variants, e.g., in the PER1 gene (circadian regulator), can modulate individual cortisol responses and indirectly affect fertility. Single cortisol measurements (e.g., from saliva) have limited reliability due to strong diurnal variation and situational factors. Therefore, fertility issues warrant comprehensive medical evaluation, including stress management and sleep optimization.