Comparison Of Clinical Characteristics Between Early And Late Patterns With Ovarian Hyperstimulation Syndrome

Objective:Ovarian hyperstimulation syndrome(OHSS) is the most serious iatrogenic disorder resulting from ovarian stimulation during IVF/ICSI cycles.It occurs either as an early(early onset) or a late pattern(late onset).The retrospective study was designed to clarify the differences in clinical characteristics between early and late OHSS and their possible clinical predictors.Methods:Among 5379 consecutive IVF/ICSI cycles,171 patients were hospitalized for moderate-to-hypersevere OHSS between January 2005 and May 2008.And We analyzied their clinical features and followed up their pregnancy outcome.Results:Early OHSS occurred in 136 patients,and late OHSS complicated 35 patients. Women with early OHSS had significantly higher peak serum E₂ levels(29275.0±11623.2pmol/L vs 16543.0±6569.3 pmol/L) on the day of hCG administration,more oocytes collected(29.86±10.55 VS 18.63±5.26 ),higher rate of basic LH/FSH ratio(＞1)(46.7%vs 25.0%) and lower gonadotropin requirements (2077.11±560.63IU vs 2241.43±728.46IU)than did in the late OHSS.The late OHSS had significantly higher embryos implantation rate(78.1%vs 39.1%),and all the late OHSS cases occurred in a pregnancy cycle,the clinical pregnancy rate(PR) fell to 50.7%in early OHSS.There were no significant differences in multiple PR, miscarriage rate,prematurity rate,new birth rate and disease severity between the two groups.In the early OHSS,there were no significant differences in disease severity between the pregnancy subgroup(n=96) and non-pregnancy subgroup(n=98).Conclusions:The early OHSS is associated with excessive ovarian response to gonadotropin stimulation,which is associated with the use of exogenous hCG.The peak serum E₂ levels,the oocyte numbers collected and LH/FSH ratio＞1 may be the clinical predictors for early OHSS.The late OHSS depends on the occurrence of pregnancy.Our findings do not support that late OHSS is more severe and closely associated with multiple pregnancies compared with early OHSS.