Objective:To investigate the correlation among the serum concentrations of vascular endothelial growth factor( VEGF) and pigment epithelium-derived factor( PEDF)with ovarian hyperstimulation syndrome( OHSS) in polycystic ovarian syndrome( PCOS) patients and to assess the predictive value. Methods:A total of 52 PCOS patients undergoing in vitro fertilization / intracytoplasmic sperm injection embryo transfer( IVF / ICSI-ET) were retrospectively analysed and separated into two groups as Group A( moderate to s...