Urdl 2005.

Methods	Open‐label, randomized trial in 65 centers in Europe and South Africa. Randomization done in 4:3 ratio (patch versus OC). Report provided information on a priori power calculation.
Participants	1517 healthy women aged 18 to 45 years. Inclusion criteria: sexually active and at risk of pregnancy, regular menstrual cycles, at least one normal menses after removal of any IUD or progestin implant, not pregnant, blood pressure < 140/90, within 35% of ideal body weight, and agree to use only the study drug as contraception and not use any other systemic steroid. Exclusion criteria: lactation or pregnancy in past 42 days, contraindication to hormonal therapy, uncontrolled thyroid disorder, abnormal Papanicolaou test, dermal hypersensitivity to topical application, smoking if > 35 years old and if OC use is restricted in this population locally, alcohol or substance abuse in past 12 months, injectable hormone use in past 6 months, use of experimental drug or device or hepatic enzyme‐inducing drug in past 30 days.
Interventions	1) 20 cm2 patch releasing norelgestromin 150 µg + EE 20 µg daily versus 2) COC containing desogestrel 150 µg + EE 20 µg. First third of women were enrolled for 13 treatment cycles and the remaining women were enrolled for 6 cycles.
Outcomes	Pregnancy, continuation, compliance, cycle control, satisfaction, adverse events. Compliance determined by daily dosing (and patch replacement information) noted on diary cards.
Notes	Corresponding investigator provided Ns for calculating satisfaction.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization conducted via interactive voice‐activated system; randomized to treatment within centers by permuted blocks.
Allocation concealment (selection bias)	Low risk	interactive voice‐activated system
Blinding (performance bias and detection bias) All outcomes	High risk	open label
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss after randomization and before treatment: 15 + 13 = 28; 28 / 1517 = 1.8% Loss to follow up: 14 + 14 = 28; 28 / 1517 = 1.8% Total loss: (28 + 261) / 1517 = 19%; patch 21% and COC 16%.