A 22-year-old woman reports having hirsutism and irregular menses. She describes unpredictable and infrequent menses (five or six per year) since menarche at 11 years of age. Dark, coarse facial hair began to develop at 13 years of age. The symptoms worsened after she gained weight in college. The physical examination includes a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 29, blood pressure of 135/85 mm Hg, and moderate hirsutism without virilization. Laboratory tests reveal a total testosterone level of 65 ng per deciliter (2.3 nmol per liter) (assay reference range, 14 to 53 ng per deciliter [0.5 to 1.8 nmol per liter]), calculated free testosterone level of 15.3 pg per milliliter (53.1 pmol per liter) (assay reference range, 0.6 to 6.8 pg per milliliter [2.1 to 23.6 pmol per liter]), and glycated hemoglobin level of 5.7% (normal value, ≤5.6%). How should this case be evaluated and managed?

Childhood obesity has become a major health concern in recent decades, especially with regard to metabolic abnormalities that impart a high risk for future cardiovascular disease. Recent data suggest that excess adiposity during childhood may influence pubertal development as well. In particular, excess adiposity during childhood may advance puberty in girls and delay puberty in boys. Obesity in peripubertal girls may also be associated with hyperandrogenemia and a high risk of adolescent polycystic ovary syndrome. How obesity may perturb various hormonal aspects of pubertal development remains unclear, but potential mechanisms are discussed herein. Insulin resistance and compensatory hyperinsulinemia may represent a common thread contributing to many of the pubertal changes reported to occur with childhood obesity. Our understanding of obesity's impact on pubertal development is in its infancy, and more research into pathophysiological mechanisms and longer-term sequelae is important.

Peripubertal obesity is associated with hyperandrogenemia and hyperinsulinemia throughout puberty, being especially marked shortly before and during early puberty. P and T concentrations in normal-weight Tanner 1-3 girls increase overnight, with similar but less evident changes in obese girls.

Polycystic ovary syndrome (PCOS) is a common clinical disorder characterized by ovulatory dysfunction and hyperandrogenaemia. A neuroendocrine hallmark of PCOS is persistently rapid LH (GnRH) pulsatility, which favours pituitary synthesis of LH over that of FSH and contributes to the increased LH concentrations and LH : FSH ratios typical of PCOS. Inadequate FSH levels contribute to impaired follicular development, whereas elevated LH levels augment ovarian androgen production. Whereas luteal phase elevations in progesterone normally slow GnRH pulse frequency, women with PCOS do not experience normal progesterone-mediated slowing, due in part to impaired hypothalamic progesterone sensitivity. This reduction in hypothalamic progesterone sensitivity appears to be mediated by elevated androgens because sensitivity can be restored with the androgen receptor blocker flutamide. The ovulatory and hormonal abnormalities associated with PCOS generally present during puberty, typically associated with hyperandrogenaemia. Along with elevated LH concentration and pulsatility, some girls with hyperandrogenaemia have impaired hypothalamic progesterone sensitivity similar to that seen in adult women with PCOS. We propose that peripubertal hyperandrogenaemia may lead to persistently rapid GnRH pulse frequency via impaired hypothalamic feedback inhibition. The subsequent abnormalities in gonadotropin secretion, androgen production and ovulatory function may support progression towards the adult PCOS phenotype.

Obesity in prepubertal and early pubertal girls is associated with reduced LH secretion and reduced nocturnal changes of LH. In later pubertal girls, obesity is linked with reduced LH amplitude, but elevated LH frequency; the latter may reflect effects of hyperandrogenemia.