Assessing hypothalamic pituitary gonadal function in reproductive disorders

Reproductive conditions secondary to disorders of the hypothalamic-pituitary-gonadal (HPG) axis are common and are associated with important health implications and con-siderable psychosocial impact. Basal and dynamic tests enable interrogation of individ-ual components of the HPG axis, facilitating diagnosis and understanding of the patho-physiology of reproductive disorders. Onset of puberty is controlled by hypothalamic gonadotrophin-releasing hormone (GnRH) neuronal function. To date, a dynamic test of hypothalamic function is not yet available. Therefore, accurate differentiation of pubertal disorders such as constitutional delay of growth and puberty (CDGP) and congenital hy-pogonadotrophic hypogonadism (CHH) as causes of delayed puberty is challenging due to similar clinical presentations and hormonal profiles. Likewise, although the two commonest reproductive disorders in women, polycystic ovary syndrome (PCOS) and functional hy-pothalamic amenorrhoea (FHA) have disparate hypothalamic function, oligo/amenorrhoea frequently poses a diagnostic conundrum owing to the overlap in the criteria used to de-fine both conditions. This review aims to describe pubertal and reproductive disorders sec-ondary to pathologies affecting the HPG axis. Challenges encountered in clinical practice in differentiating pubertal and reproductive conditions are reviewed in conjunction with the utility of baseline and dynamic endocrine tests to interrogate specific components of the HPG axis. We also highlight putative hypothalamic, pituitary, and gonadal markers in devel-opment that could improve the diagnosis of patients presenting with disorders of puberty or reproduction.

Automated summary

Reproductive conditions caused by disorders of the HPG axis have significant health implications and psychosocial impact. Basal and dynamic tests are useful in diagnosing and understanding the pathophysiology of reproductive disorders. Differentiating pubertal and reproductive disorders can be challenging due to similar clinical presentations and hormonal profiles. This review aims to describe the various disorders affecting the HPG axis and the challenges faced in clinical practice, as well as the utility of endocrine tests in investigating specific components of the HPG axis.