Abstract: AIM: To compare the efficiency of prednisone and 6% hydroxyethylstarch in the prevention of moderate and severe ovarian hyperstimulation syndrome (OHSS). METHODS: A total of 207 OHSS high-risk patients and 207 cycles of in vitro fertilization and embryo transfer (IVF-ET) programme with estradiol serum concentration≥4000 pg/mL on the day of hCG injection and/or≥15 oocyte collection were prospective and randomized divided into A, B and C three groups. The patients in group A (66 cycles) orally took prednisone 5 mg tid on the day of hCG injection for 2 d, and then changed to 5 mg qd for 5 d; the patients in group B (75 cycles) were infused with 500 mL 6% hydroxyethylstarch on the day of oocyte collection for 3d; the patients in group C (66 cycles) were treated with prednisone and hydroxyethylstarch. The incidence of moderate and severe OHSS and the other corresponding indexes among the three groups were analyzed. RESULTS: There have 60 cycles were transferred in group A, clinical pregnancy rate was 50% and the incidence of moderate and severe OHSS was 3.03%; 65 cycles were transferred in group B, clinical pregnancy rate was 44.6%, and the incidence of moderate and severe OHSS was 13.33%; 59 cycles were transferred in group C, clinical pregnancy rate was 42.4% and the incidence of moderate and severe OHSS was 3.03% .There was no significant difference in pregnancy outcome among the three groups (P>0.05), but the incidence of moderate and severe OHSS in group B was higher than those in group A and group C (P<0.05). CONCLUSION: Oral administration of prednisone have no effect on pregnant rate of IVF and it is a cheaper, more convenient and effective alternative to 6% hydroxyethylstarch in moderate and severe OHSS prevention.

Key words: In vitro fertilization, Ovarian hyperstimulation syndrome, Prednisone, Hydroxyethylstarch