Objective: Hyper- and hypoestrogenism that persist for a long time can affect vascular and metabolic function. However, it is not clear whether the same is true for subtle sex hormone changes (i.e., during the menstrual cycle).
Methods: Twenty-one healthy normal-weight women with regular cycles were studied during the early-follicular (day 3 +/- 2), late-follicular (day 12 +/- 2), and midluteal (day 20 +/- 3) phases. Microvascular function was assessed by skin iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), by skin-capillary recruitment after arterial and venous occlusion (i.e., capillaroscopy), and by Fourier analysis of resting skin laser Doppler flow at rest (i.e., vasomotion). Insulin sensitivity (i.e., homeostasis model assessment) and blood pressure were also determined during the study days.
Results: Three women were excluded from analyses because they were anovulatory. Skin microvascular responses to ACh and SNP, capillary function, vasomotion, insulin sensitivity, and blood pressure did not differ between the three phases (P > or = 0.1). Further, microvascular function did not correlate with plasma-estrogen levels (r = -0.06-0.2; P> or = 0.2).
Conclusions: Microvascular function does not demonstrate a clear menstrual-cycle-dependent variation.