Increased Serum AMH in a Subgroup of Women with Idiopathic Hyperandrogenism: Do These Women Have PCOS?

<b>Background:</b> Idiopathic Hyperandrogenism (IH) is often encountered in the general population and particularly in women presenting with androgen excess. It is diagnosed in women who have normal ovulatory cycles, elevated androgen levels, and normal appearing ovaries on ultrasound. Using serum anti-mullerian hormone (AMH), which has been suggested to be a surrogate marker of polycystic ovarian morphology, we wished to determine if some women with IH may have the ovulatory phenotype of PCOS, where metabolic abnormalities may be more prevalent. <b>Methods:</b> This was a retrospective study of 84 women diagnosed with IH and 50 age- and BMI-matched ovulatory controls who were evaluated between 2021 and 2024. Androgen levels, ovarian ultrasound, and serum AMH were assessed. In addition, glucose, insulin, HOMA-IR, and lipid levels were measured. <b>Results:</b> Twenty-four women (29%) with IH had elevated AMH levels (>4.7 ng/mL). None of the control women had elevated values. These 24 women with IH had values ranging from 5.5-11.9 ng/mL, compared to the other 60 women whose AMH levels were 0.8-4.3 ng/mL. Age and weight were similar in these two subgroups of women with IH. Glucose, insulin, and HOMA-IR were similar in the two groups, but cholesterol and LDL-cholesterol were elevated in the 24 women with elevated AMH. Elevations in LDL-cholesterol were observed in 3.5% of the women with normal AMH and in 21% of those with elevated AMH. <b>Conclusions:</b> Despite normal ovarian morphology on ultrasound, approximately 30% of women with IH were found to have elevated AMH and may be considered to have the ovulatory phenotype of PCOS. These women also have some metabolic dysfunction, which is more characteristic of women with PCOS. These data reinforce the notion that AMH findings are not always concordant with ovarian morphological findings and suggest wider implication of elevated AMH levels in the pathophysiology of PCOS.