Abstract

The purpose of the present study was to investigate the stability of vascular endothelial growth factor (VEGF) in plasma samples and the influence of ovarian hyperstimulation on systemic levels of VEGF. Stability assays for VEGF in plasma samples revealed significant increases following even short incubations of samples at room temperature (< or = 2 h, p < 0.001). To investigate a possible impact of controlled ovarian hyperstimulation (COH) on peripheral VEGF levels, serial blood collection over one menstrual cycle was performed in unstimulated as well as in gonadotropin-stimulated cycles for in vitro fertilisation/embryo transfer (IVF/ET) (10 women each). Peripheral levels for VEGF were significantly higher in gonadotropin stimulated cycles as compared to non-stimulated cycles (p < 0.001). There was no significant difference between follicular phase and luteal phase levels in either group. VEGF levels tended to correlate with the number of follicles detected by vaginal sonography prior to oocyte aspiration (p = 0.051). In conclusion, VEGF levels are elevated in gonadotropin-stimulated IVF/ET cycles as compared to natural cycles.