Elective cryopreservation of embryos at the pronucleate stage in women at risk of ovarian hyperstimulation syndrome may affect the overall pregnancy rate.

The aim of this retrospective study was to assess the pregnancy outcome and incidence of severe ovarian hyperstimulation syndrome (OHSS) in patients at risk of developing OHSS who had embryo cryopreservation at pronucleate stage and deferred embryo transfer in a university-affiliated teaching hospital over a 5-year period. Elective embryo cryopreservation and deferred transfer in patients at risk of OHSS does not compromise the cumulative pregnancy rate per patient and also results in a low overall incidence of severe OHSS.