| Methods |
Randomized controlled trial without blinding. The method of randomization is not described. The author could not elucidate the method of randomization. |
| Participants |
342 women at 11 sites in the USA. 53 women did not start the study after randomization. Inclusion criteria were healthy women aged 18 to 35 years for smokers and no upper age limit for non‐smokers with regular menstrual cycles (25 to 31 days) for the 3 months before enrollment who were at risk of becoming pregnant. Exclusion criteria were the standard contraindications for oral contraceptive studies listed in product class labeling, use of oral contraceptives within the previous 3 cycles before enrollment, use of an IUD or injectable or implantable estrogens, progestins or androgens during the 6 months before enrollment, smoking of more than 15 cigarettes per day and drug or alcohol abuse. |
| Interventions |
Triphasic norethindrone/ethinylestradiol (500‐750‐1000 μg NET and 35 μg ethinylestradiol in a 7/7/7 days regimen and 7 days of placebo tablets, N=173) [Ortho‐Novum 7/7/7] versus
monophasic levonorgestrel/ethinylestradiol (100 μg LNG and 20 μg EE for 21 days and 7 days of placebo tablets, N=169) [Alesse/Loette]. |
| Outcomes |
Principal outcome measures are: pregnancy; side effects; cycle control; discontinuation and reasons for discontinuation. Use of a daily diary card to collect data on pill intake, cycle control, side effects and concomitant medication. Spotting was defined as a light flow that did not require sanitary protection; breakthrough bleeding as a heavier flow, similar to normal menstrual flow, that required sanitary protection; withdrawal bleeding as bleeding or spotting that began during the drug‐free interval and stopped by day 4 of the next cycle; intermenstrual bleeding as all other bleeding or spotting; and an amenorrheic cycle as one with no withdrawal bleeding or intermenstrual bleeding. Report describes the results of 4 cycles of exposure. In the article there is a discrepancy in the number of pregnancies. Communication with the authors revealed that one participant in the monophasic group became pregnant before the start of the study. |
| Notes |
The report does not provide an a priori hypothesis or a sample size or power calculation. Study duration: 4 cycles. 75 women in the triphasic group and 76 women in the monophasic discontinued early. The reasons for discontinuation are described. 23 women in the triphasic group and 30 women in the monophasic group did not start oral contraceptives. 12 women in the triphasic group and 9 women in the monophasic group were lost to follow up. 9 women in the triphasic group and 5 women in the monophasic were withdrawn because of protocol violations. Analysis not according to intention‐to‐treat principle. Breakthrough bleeding includes both breakthrough bleeding and spotting in this review. The trial was sponsored by the manufacturer of the studied monophasic levonorgestrel/ethinylestradiol pill (Wyeth‐Ayerst). |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment (selection bias) |
Low risk |
Not described in paper. Communication with an author indicated allocation concealment by sequentially‐numbered opaque envelopes. |
