['To determine intrauterine levels of vascular endothelial growth factor (VEGF)-A during the menstrual cycle in the human female and to investigate the impact of decidualization and corpus luteum function.', 'Prospective clinical study.', 'Tertiary university center.', 'Fifty-four women with infertility problems.', 'Intrauterine concentrations of VEGF-A were determined at various time points during the secretory phase using a novel intrauterine microdialysis device. Concomitantly, intrauterine insulin-like growth factor binding protein (IGFBP)-1 levels served as a paracrine parameter for decidualization. Serum progesterone (P) and E(2) levels were determined as markers for corpus luteum function. Intrauterine VEGF levels.', 'The VEGF levels in utero were clearly cycle dependent with increasing levels during the late secretory and premenstrual phases. There was a significant correlation with the decidualization marker IGFBP-1. In contrast, intrauterine VEGF levels showed a significant negative correlation with serum E(2) and P.'] Is cycle dependency of intrauterine vascular endothelial growth factor levels correlated with decidualization and corpus luteum function?