Plasma VEGF concentrations showed no cyclicity in fertile women, but were higher in the infertile group at the midluteal phase. Serum sVEGFR-1 concentrations were similar between the groups and between natural and IVF cycles. However, in infertile women, concentrations of sVEGFR-1 increased from the follicular phase to the luteal phase. In the follicular phase infertile women had a high ratio of VEGF/sVEGFR-1, which was decreased in the luteal phase