Circulating hormones, EEG, and performance in psychological tests of women with and without oral contraceptives

Abstract

A comparative study was conducted to examine the interrealtionships between changes in circulating hormomes and the EEG and the performance in psychological tests both of women with normal menstrual cycles and of women using oral contraceptives. EEG and psychological data are analyzed in detail. Blood samples were taken at 2-day intervals for 16 women on normal menstrual cycles and for 16 women on pills. The hormonal results confirmed previous studies. Only the alpha-rhythm of the EEG was slightly but significantly accelerated during the luteal phase of the menstrual cycle, as a result of the influence of progesterone. Oral contraceptive tend to slow the alph-rhythm. In performance tests for reaction time and mathematical ability, scores were better during the luteal phase when increased estradiol and progesterone levels occur but not as good during the immediate preovulatory phase when only estradiol levels are high. The groups using oral contraceptive reacted significantly slower during the luteal phase. This result indicates that 1 or more of the ingredients of combined oral contraceptives may interfere with mental abilities. It is concluded that there is a definite relationship between the alpha-rhythm of the EEG, performance time and quality, and reaction time and between these factors and the levels of progesterone whichchange during the menstrual cycles.