ASSESSING THE RISK OF OVULATION IN INTERACTION STUDIES OF DRUGS AND ORAL-CONTRACEPTIVES

When certain drugs are taken concomitantly with an oral contraceptive, the efficacy of the contraceptive may be obtunded, and pregnancy may ensue. Since the function of oral contraceptives is to suppress ovulat ion, the risk of ovulation is an important parameter in clinical studi es investigating interactions between drugs and oral contraceptives. T he purpose of this paper is to compare a crossover design, and a new s tudy design used for assessing a possible interaction between a drug a nd an oral contraceptive, and to discuss the statistical issues involv ed in the planning and evaluation of the results of such studies.