Early and late ovarian hyperstimulation syndrome: early pregnancy outcome and profile

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) in IVF/ICSI cycles may occur either as an early (early onset) or a late pattern (late onset). This observational study was designed to identify whether the onset pattern of OHSS is associated with the occurrence of pregnancy and the early pregnancy outcome. METHODS: Among 4376 consecutive IVF/ICSI cycles, 113 patients were hospitalized for OHSS after IVF/ICSI treatment and were included in the study. The setting was the Dutch-speaking Brussels Free University Hospital, between June 2000 and September 2002. RESULTS: Early OHSS occurred in 53 patients, and late OHSS complicated 60 patients. A total of 96.7% of the late OHSS cases occurred in a pregnancy cycle and were more likely to be severe than the early cases (P