Endometrial perfusion across the normal human menstrual cycle assessed by laser Doppler fluxmetry

This study investigated variations in microvascular perfusion of human endometrium across the menstrual cycle, using a laser Doppler technique to assess red blood cell (RBC) flux. Endometrial RBC flux was monitored by laser Doppler fluxmetry via a fibre optic probe inserted transvaginally into the uteri of 19 conscious normal volunteer women, on four occasions at weekly intervals over one menstrual cycle. Regional variation in RBC flux was investigated in 16 surgical patients under general anaesthesia and in five excised uteri. Endometrial perfusion exhibited short-term temporal variations consistent with the cardiac cycle and often also showed vasomotion (5-12 cycles/min). Mean endometrial perfusion differed between phases of the menstrual cycle in conscious women, being highest during early proliferative and early follicular phases. There were no significant regional differences in local mean endometrial perfusion in anaesthetized patients. No evidence of endometrial ischaemia/reperfusion episodes was found in any subject using this technique. This study provides benchmark data of variations in RBC flux per unit volume of tissue in the luminal approximately 1 mm of endometrium, across the normal human menstrual cycle. Flux values were highest at times associated with endometrial growth and preparation for implantation, indicating that RBC flux may be a useful parameter for assessment of endometrial physiology.