Context: AMH levels are increased in polycystic ovarian syndrome (PCOS), but it is not known whether other forms of hyperandrogenism, such as PCOS observed in women with type 1 diabetes mellitus (DM1), are also associated with elevated AMH levels.

Objective: To compare AMH and steroid levels in women with PCOS with and without DM1.

Design: We compared the clinical, hormonal and ultrasonographic characteristics of 17 women with PCOS and DM1 (DM1+PCOS), 20 women with PCOS without DM1 (PCOS) and 35 normal women (Control) in a cross-sectional study.

Results: The Ferriman-Gallway score, serum testosterone, free androgen index and 17OH-Progesterone, and ovarian volume were elevated in both groups of PCOS women compared to controls. Serum androstenedione, LH/FSH ratio and follicle number, however, were higher and SHBG was lower, in PCOS compared to DM1+PCOS and Controls.

AMH levels were higher in PCOS (76.0 ± 36.3 pmol/L) than in DM1+PCOS (18.8 ± 7.4 pmol/L) and Controls (13.9 ± 8.3 pmol/L). AMH levels correlated with follicle number in the three groups. Serum AMH/follicle number ratio was higher in PCOS than in DM1+PCOS and Controls.

Conclusions: Women DM1+PCOS have normal levels of AMH, inhibin B, estradiol, SHBG and LH/FSH, suggesting that the pathophysiology of hyperandrogenism in PCOS patients with DM1 appears to be different from that in PCOS without DM1. However, hirsutism score and androgen levels were similar in both groups of women with PCOS. We postulate that insulin treatment acts as a co-gonadotropin increasing follicle recruitment, hence not increasing AMH levels.