EPO and ovarian hyperstimulation syndrome: Furthermore, there was no difference (p = 0.74) in circulating Epo between the IVF group at OPU7 (12.5; 95% CI 10.3–13.4 IU/L) and early OHSS group on the worst day of symptoms (median OPU6; 12.0; 8.8–17.2 IU/L).