A preliminary study of the effects of menstrual cycle on sleep instability using cyclic alternating pattern method

This study was aimed to clarify the changes in Non-REM sleep by menstrual cycle using polysomnography with the Cyclic Alternating Pattern (CAP) analysis. The subjects were twelve healthy women having regular menstrual cycles (mean age: 29.5 ± 4.4 years old). As the results of our study, the conventional sleep parameters did not significantly differ between different phases of the sexual cycle. However, the CAP rate, which represents instability of sleep, was significantly higher in Luteal phase (Lp) than in Follicular phase (Fp) (Lp: 38.7 ± 2.81 %, Fp: 28.6 ± 1.8). It was suggested that the worsening of sleep instability might cause the lowered sleep quality in Lp.