| Methods |
Six sites in Norway, two in Sweden and one in Denmark.
12 treatment cycles.
Double‐blinded but did not specify who was blinded. |
| Participants |
Women aged 18 to 35 (Norway sites) or 18 to 40 (Sweden and Denmark sites) years.
Excluded heavy smoking among women 35 years of age; risk factors for or history of certain diseases; lactation; and certain antibiotics. |
| Interventions |
EE 20 µg and desogestrel 150 µg (N=500) versus EE 30 µg and desogestrel 150 µg (N=500). |
| Outcomes |
Contraceptive efficacy, cycle control, and side effects.
'Withdrawal' bleeding defined as bleeding that began within the pill‐free period and did not exceed eight days. 'Irregular' bleeding defined as any other bleeding. |
| Notes |
Allocated with simple random table.
Excluded randomized women from the analysis.
67% (672/1000) completed study. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Unclear risk |
Allocation concealment not reported. |
