Morphologic Changes in Urine Particles during the Menstrual Cycle

Our previous study demonstrated that the numbers of epithelial cells and erythrocytes in midstream urine vary significantly during the menstrual cycle (1). We now report the influence of the menstrual cycle on the number and morphology of urine particles. Specimens were obtained from 67 healthy female students (age range, 18–20 years) at the College of Medical Technology. All participants gave written, informed consent; were asymptomatic; and provided information about their menstrual cycles. None had urologic conditions at the time of the study. Participants were instructed to collect midstream urine samples in sterile containers. Particles in midstream urine were analyzed by use of a fully automated urine cell analyzer, the UF-100 (Sysmex Corporation), within 2 h of collection. Specimens were classified into 3 groups according to the number of days after menstruation: …