Early and Late Ovarian Hyperstimulation Syndrome: Two Distinct Clinical Entities

Objectives: To study the differences in clinical characteristics of early and late ovarian hyperstimulation syndrome (OHSS) and its association with the occurrence of pregnancy and early pregnancy outcome Design: Prospective study Setting: Department of Obstetrics and Gynecology, Institute of Kidney Diseases and Research Center, Ahmedabad, India Subjects: Thirty patients who developed OHSS out of 324 IVF / ICSI cycles over a one-year period Intervention: All patients developing OHSS were hospitalized and managed conservatively. Main Outcome Measures: Incidence of OHSS at our center, OHSS and pregnancy outcome and their course in the hospital Results: Early OHSS occurred in 18 patients and late OHSS complicated 12 patients, the overall incidence being 7.7%. Early OHSS patients as compared to late OHSS group were characterized by significantly higher serum estradiol (E2) levels and the number of follicles on the day of hCG administration, and the number of oocytes retrieved. Clinical pregnancy occurred in all cycles with late OHSS. No significant difference was observed in occurrence of multiple pregnancy between the two groups. Late OHSS cases were more severe than early cases. Conclusion: Serum E2 levels, the number of follicles on the day of hCG administration, and the number of oocytes retrieved can be used to predict the occurrence of early OHSS.