Rhythmic changes of human female uroepithelial squamous cells during menstrual cycle. Transmission and scanning electron microscopic study.

The cellular component of the fluid of female urethral expulsions was analysed in two healthy women (37-year-old multipara and 27-year-old nullipara) on days 1, 10, 12, 14, 26 and 27 of their menstrual cycle. Transmission and scanning electron microscopy were used to determine standard values of uroepithelial squamous cells of the fluid of female urethral expulsions on different days of the menstrual cycle. In agreement with the known changes of these cells found in cytological smears during the cycle, electron microscopy confirmed characteristic changes in the appearance of the fine cell structure and the space configuration of the squamous cells. Changes in the desmosomal junctions among squamous cells during the cycle were found. Striking adherence of bacteria and mucosubstances to the squamous cell surfaces were observed in the first half of the menstrual cycle and at the time of ovulation.