Changes in the EEG during menstrual cycle of women with and without oral contraceptives

Abstract

This chapter investigates the changes in the electroencephalography (EEG) during menstrual cycle of women with and without oral contraceptives. Bipolar temporo-central EEG records were made from 32 young and healthy women at 2-day intervals. One-half of the women had spontaneous menstrual cycles; the others were under combined oral contraceptives (o. C's). A period of 2 min at the beginning and at the end of each 10 min record was analyzed and the power spectra of each period were plotted. For proper timing of the follicular and luteal phases the serum levels of Luteinizing hormone (LH), Follicle-stimulating hormone (FSH), prolactin, progesterone and estradiol were measured by radioimmunoassays. Power-spectral analysis of the α-rhythm of the EEG revealed the following results: in spontaneously cycling women, the absolute power of the a-rhythm in the 10.5-13 Hz range (fast a-component) was about twice as high as in the 8-10.5 Hz range, whereas in women under o. C's the power of the fast and slow x-component was evenly distributed. In addition, the chapter also describes the variations of performance in psychological tests during the menstrual cycle in women with and without oral contraceptives.