Coasting acts through downregulation of VEGF gene expression and protein secretion

BACKGROUND: This study was conducted to investigate the mechanisms by which coasting may be effective in decreasing the incidence of ovarian hyperstimulation syndrome (OHSS). METHODS: A total of 160 women (patients and oocyte donors) undergoing coasting and 116 controls were included in the study. Serum, follicular fluid and granulosa cells were collected on the day of oocyte retrieval. Vascular endothelial growth factor (VEGF) concentrations were determined using an enzyme‐linked immunosorbent assay (ELISA). Real‐time PCR was performed to evaluate VEGF gene expression in granulosa cells. Cell death was studied by flow cytometry using annexin V–fluorescein isothiocyanate (FITC) and counterstaining by propidium iodide, and double staining with CD45 monoclonal antibody was performed to distinguish the contamination of apoptotic leukocytes. RESULTS: Follicular cells aspirated from coasted patients showed a ratio in favour of apoptosis, especially in smaller follicles (48 versus 26%, P