A Placebo-Controlled Double-Blind Crossover Investigation of the Side Effects Attributed to Oral Contraceptives

Abstract

398 new users of oral contraceptives at the Research Clinic of the Southwest Foundation Texas were asked if they experienced nausea vomiting headache or breast discomfort nervousness or depression and had weight and blood pressure recorded in the pretreatment cycle and at monthly visits. Each received placebo Oracon (sequential) Ovulen-21 (combination) Norinyl-1 or .5 mg chlormadinone acetate in a double-blind protocol incorporating a pretreatment placebo cycle crossover to an active pill for 4 cycles and 2 more crossovers for Cyles 5 and 6. The only symptoms significantly higher than in the pretreatment (placebo) cycle were nausea and vomiting with Oracon (p greater than .05) and headache with Ovulen (p greater than .05). Pointing out that the highest incidence of complaints occurred in the placebo cycle the authors conclude that controls are necessary in contraceptive trials but the first cycle is not valid for comparison.