Pressure-controlled hysteroscopy during menstruation

STUDY OBJECTIVE: To document the hysteroscopic appearance of the endometrium at various stages of menstrual shedding and regeneration. DESIGN: Prospective observational study. SETTING: University hospital. PATIENTS: Fourteen women at various stages of the bleeding phase of the menstrual cycle who had not received hormonal therapy during the previous 2 months and who had regular menstrual cycles of 27 to 30 days. INTERVENTION: Twin-channel continuous flow hysteroscopy and careful control of intrauterine pressure. MEASUREMENTS AND MAIN RESULTS: Pressure-controlled hysteroscopy enables a safe and clear view of the endometrium at every stage of the bleeding phase of the menstrual cycle. Menstruation involves piecemeal shedding and concurrent regeneration in adjacent areas. It begins with subepithelial hemorrhage, followed by linear splitting of the surface epithelium and superficial functionalis. Islands of such superficial endometrium are progressively undermined and break free from the underlying tissues. This exposes a mesh of "skeletonized" tubules composed of both glandular stumps and vascular elements. These form the scaffolding for the subsequent reepithelialization and are soon buried beneath a newly formed layer of epithelium and stroma. CONCLUSIONS: Pressure-controlled hysteroscopy enables visualization of the surface appearance of menstrual shedding and regeneration. The process is piecemeal, with zones of rapid shedding and regeneration occurring concurrently over a number of days.