Oral contraceptive potencies and side effects.

A set of empirical results is used to test a model that assigns rankings to oral contraceptives in terms of relative hormonal potencies. The association between the observed incidence of side effects attributed to excess of estrogen and progestin and their incidence as predicted by the model is analyzed. Results of the study show the model to have incorrectly predicted the observed ranking order of symptoms associated with excess estrogen. Further, while the model correctly predicted the oral contraceptive with the highest progestogenic potency (Ovral), the observed ranking order of the other two preparations is shown to be the reverse of that predicted by the model.