Insulin sensitivity in non-obese women with polycystic ovary syndrome during treatment with oral contraceptives containing low-androgenic progestin

BACKGROUND: Combined oral contraceptives (COC) effectively suppress hyperandrogenism in women with polycystic ovary syndrome (PCOS), though deterioration of insulin sensitivity during treatment is assumed. The study aim was to investigate insulin action and androgen production during treatment with COC containing low-androgenic progestin. METHODS: A total of 13 PCOS women and nine controls was enrolled into the study. Only non-obese women with a body mass index (BMI) less than or equal to30 kg/m(2) were included. Hyperinsulinaemic euglycaemic clamp techniques were performed before and after 6 months of treatment with a monophasic COC containing norgestimate. RESULTS: Anthropometric parameters [BMI, waist:hip ratio (WHR)] remained unaltered during the study in both groups. No deterioration in glucose disposal rate (M), insulin sensitivity index (ISI) or metabolic clearance rate of glucose (MCRG) was observed during treatment in PCOS subjects. Fasting glucose decreased significantly (P < 0.01), but fasting insulin remained unchanged. Significant decreases in concentrations of testosterone (P < 0.001), androstenedione (P < 0.01) and dihydroepiandrosterone (DHEA) (P < 0.001), a decrease in the free androgen index, and an increase in concentrations of sex hormone-binding globulin were found in PCOS subjects. CONCLUSIONS: The norgestimate-containing COC significantly decreased androgen production and concentrations of free androgens, without reducing insulin sensitivity in non-obese PCOS subjects.