Evaluating triphasic oral contraceptives: the rationale for a randomized trial.

Abstract

The randomized clinical trial is one of the major achievements of our times. Randomized trials set the standard for scientific rigor. They are medicine's closest approximation to the controlled experiments of the laboratory scientist. These studies prevent selection bias and minimize ascertainment bias. In addition, they are statistically efficient. There have been few randomized clinical trials comparing the metabolic effects and adverse drug experiences of low-dose oral contraceptives. Previous studies conducted with oral contraceptives containing higher doses of estrogen (equivalent to greater than 50 micrograms of ethinyl estradiol) may not be relevant today when low-dose preparations are more widely used. For this reason a randomized trial was conducted to compare three multiphasic oral contraceptives marketed in the United States.