Skin tissue water and laser Doppler blood flow during a menstrual cycle

Previous work offers conflicting evidence concerning whether basal skin blood flow (SBF) varies with the menstrual cycle. Our goal was to determine the extent of cycle-dependent changes in forearm SBF parameters and if they are linked to local tissue water content and arm volume changes. Both arms of 10 premenopausal women were evaluated three times during their cycle (days 4, 12 and 22) and 10 postmenopausal women were evaluated once. Each evaluation included laser Doppler blood flow parameters (perfusion, volume and velocity), skin temperature, arm volume and local tissue water determined by a new tissue dielectric constant method. Estradiol and progesterone concentrations were determined at each visit by using saliva samples and analysis showed the expected pattern of variation over the cycle. Main results showed no significant cycle-dependent variations in any SBF parameter, temperature, tissue water or arm volume. Postmenopausal women had significantly less estradiol levels, but did not differ with respect to premenopausal women in any measured parameter except for a slightly less blood velocity (P<0.01). We hypothesize that that the absence of changes in tissue water and arm volume in our group may account for the constancy of the measured SBF parameters. However, in other populations, hormonally induced tissue changes may occur and contribute to the cycle-dependent changes in resting blood perfusion that have been reported. This possibility suggests that it may be useful to measure and report a skin tissue water index when serial changes in blood perfusion are being investigated.