Sleep and the balance of female hormones are closely related. 90 Days: My Sleep Reflection DIARY is a self-care tool based on the concept of living in good health by understanding the nature of female hormones and life stages, reviewing lifestyle habits centered on daily sleep, and stabilizing the axis of body and mind. Packed with information on sleep and female hormones, it helps women understand their physical and mental state by journaling their sleep condition and menstrual cycles on original worksheets.