['Endometrial NK cells play a critical role in uterine vascularization producing angiogenic factors. Impact of ovarian stimulation on endometrial expression of NK cells and VEGF in normal fertile oocyte donors and the effect of endometrial injury treatment on these parameters have been investigated.', 'Endometrial tissue was obtained from oocyte donors during natural and stimulated cycles. NK cell subsets were measured by flow cytometry. VEGF was determined by ELISA and flow cytometry. Endometrial angiogenic parameters were determined by ultrasound Doppler. Local injury was induced by scratching endometrial tissue previous to implantation window.', 'Ovarian stimulation decreased endometrial levels of NK cells and vascularization index but increased VEGF levels. Local injury normalized only the CD56(+) NK cell count.'] Does ovarian stimulation affect the levels of regulatory endometrial NK cells and angiogenic cytokine VEGF?