| Methods |
Randomized controlled trial. The method of randomization, the use of allocation concealment and the use of blinding are not described. Communication with the author revealed no extra information. |
| Participants |
555 women at sites in Austria, Germany, the Netherlands and the United Kingdom. The report does not provide inclusion/exclusion criteria for the study. Little information about baseline demographics. The paper does not report if switchers were included in the study. |
| Interventions |
Triphasic levonorgestrel/ethinylestradiol (50‐75‐125 μg LNG and 30‐40‐30 μg EE in a 6/5/10 days regimen, N=278) [Triquilar/Logynon] versus
monophasic desogestrel/ethinylestradiol (150 μg DSG and 30 μg EE, N=277) [Marvelon]. |
| Outcomes |
Primary outcome measures are: pregnancy; side effects; cycle control; continuation and reason for discontinuation. Use of a bleeding chart to collect data on cycle control. Data on side effects were recorded if reported spontaneously. The report does not describe the definitions of breakthrough bleeding and spotting. |
| Notes |
The report does not provide an a priori hypothesis. Report states a sample size, yet the sample size calculation is unclear. Study duration: 6 cycles. Limited information on number and reasons for discontinuation. The paper describes that 15.5% of the participants discontinued early but provides no breakdown of how many were in each group. The report does not mention loss to follow up or withdrawals because of protocol violations. Unclear whether the analysis was according to intention‐to‐treat principle. The trial was supported by the manufacturer of the studied triphasic levonorgestrel/ethinylestradiol pill (Schering). |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Unclear risk |
No information |
