Alteration of shock aversion thresholds during the menstrual cycle

Aversion thresholds for electrical shock were obtained from 5 males, 6 females who were taking oral contraceptives, and 12 females who were not. All subjects were volunteers from introductorylevel psychology courses. Measures were repeated 3 times per week for 5 weeks. Males and females taking oral contraceptives showed no cyclic fluctuations in threshold. The other female group had significant (p < .025) fluctuations in threshold, from a maximum at ovulation to a minimum 1 week after the onset of the menses.