| Methods |
Randomized controlled trial without blinding. Randomization in balanced blocks of 6. The method of randomization was not described. Communication with the author indicated a computer‐generated randomization sequence |
| Participants |
463 women at 15 sites in the US. Inclusion criteria were age 18 to 50 years, BMI of 18 to 35, regular menstrual cycles of 21 to 38 days. Exclusion criteria were contraindications to oral contraceptive use, age more than 35 years and smoking more than 15 cigarettes per day, more than 2 alcoholic drinks per day, breastfeeding, fewer than 3 regular cycles after delivery or fewer than 2 regular cycles after an abortion, use of injectable or implant contraceptives within 6 months before enrollment or considered to be poor candidates for follow up or reliability. Analysis of 2 groups: 308 switchers (participants who have used OC in the 2 months before the study); 155 starters. 34 participants were using 20 μg EE preparations and 262 were using 30 or 35 μg EE preparations at study entry. Low percentage of smokers. |
| Interventions |
Triphasic norgestimate/ethinylestradiol (180‐215‐250 μg NGM and 35 μg EE in a 7/7/7 days regimen, N=155) [Tri‐Cyclen] versus
monophasic levonorgestrel/ethinylestradiol (100 μg LNG and 20 μg ethinylestradiol for 21 days and 7 hormone‐free days, N=154) [Alesse] versus
monophasic desogestrel/ethinylestradiol (150 μg DSG and 20 μg EE for the first 21 days, then 2 hormone‐free days, and 10 μg EE for the last 5 days, N=154) [Mircette]. |
| Outcomes |
Primary outcomes measures are: efficacy; cycle control; side effects; and continuation rates. Use of a daily diary to collect data on pill‐intake, side effects and cycle control. Cycle control was assessed by an index that considered duration and severity of intermenstrual bleeding. The report does not describe the definitions of breakthrough bleeding and spotting. Limited information on outcome measures. |
| Notes |
The report does not provide an a priori hypothesis or a sample size or power calculation. Study duration: 6 cycles. The paper describes continuation rates; however, the number of women who continue are not described. Communication with the author indicated that 25 women in the triphasic group, 26 women in the levonorgestrel monophasic group and 24 women in the desogestrel monophasic group discontinued early. Reasons for discontinuation are not described. It is unclear whether the analysis was according to intention‐to‐treat principle. The trial was supported by the manufacturer of the monophasic desogestrel/ethinylestradiol pill (Organon). |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Low risk |
Not described in report. Communication with the author indicated allocation concealment by sequentially numbered randomization cards with an opaque scratch‐off dot. |
