Guida 2005.

Methods	Randomized unblinded trial conducted in Italy from August 2003 to December 2003.
Participants	56 women attending the family planning clinic. Inclusion criteria: 22 to 34 years old, reached menarche at 12 to 14 years old, BMI between 20 and 22 kg/m2, sexually active with habitual partner, no abnormal menstrual cycles, and no abnormal dietary requirements. Exclusion criteria: pregnancy or breastfeeding in past year, hepatic disease, vascular or metabolic disorder, > 10 cigarettes/day, history of migraine, use of psychotropic drugs or drugs that affect pharmacokinetics of contraceptive steroids, use of hormonal contraceptives in past year, hysterectomy or oophorectomy, and other contraindications for hormonal contraceptives.
Interventions	Vaginal ring releasing etonogestrel 120 µg + EE 15 µg daily versus COC containing desogestrel 150 µg + EE 20 µg; 6 treatment cycles.
Outcomes	Continuation. Report focused on sexual life satisfaction.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization sequence was "computer‐generated".
Allocation concealment (selection bias)	Low risk	Report states that randomization sequence was concealed until after assignment, but does not state how it was concealed.
Blinding (performance bias and detection bias) All outcomes	High risk	unblinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Randomized = 56 Total loss: 5/56 = 9%; ring 7% and COC 11%