Comparison of spontaneous and contraceptive menstrual cycles on a visual discrimination task.

21 women with spontaneous ovulatory menstrual cycles, and 7 women who were regular users of oral contraceptives were investigated over two consecutive menstrual cycles. There two groups were compared on their two flash threshold performance and on mood ratings. It was found that, for women with ovulatory menstrual cycles, visual sensitivity was enhanced during the late follicular phase of the cycle, as ovulation approached. At other phases of the menstrual cycle (paramenstrual and luteal) visual sensitivity remained constant and comparable to the values found in women who were taking to the values found in women who were taking contraceptives. Women who were taking contraceptives showed no significant variation in visual sensitivity with phase of the menstrual cycle. The overall level of anxiety, as reflected by mood ratings was higher in women with spontaneous cycles compared to those taking contraceptives. Neither group, however, showed significant variation in anxiety with phase of the cycle.