Haverinen A, Kangasniemi M, Luiro K, et al. - Researchers conducted this randomized, controlled 9-week clinical trial to compare the effects of two formulations of combined oral contraceptives (COCs), estradiol valerate (EV) and ethinyl estradiol (EE) combined with dienogest (DNG), and DNG-only, on glucose tolerance. Age 18–35 years, regular menstrual cycle (28 ± 7 days), no polycystic ovaries, non-smoking, no contraindications for COC use and a 2-month wash-out from hormonal contraceptive use, were the criteria for inclusion. Study participants were randomized to EV+DNG (n = 20), EE+DNG (n = 20), and DNG-only (n = 19), and evaluated at baseline, at 4-5 weeks and 8-9 weeks of treatment. Fifty-nine women participated, and the research was completed by 56 women. No clinically relevant differences were observed between EV and EE combined with DNG and DNG-only on glucose tolerance in healthy, young, normal-weight women, suggesting that when used continuously for nine weeks, these preparations tend to be close to neutral in terms of glucose metabolism.