The efficacy of the transfer of twice frozen-thawed embryos with the vitrification method.

To confirm the clinical benefits of recryopreserved, twice-thawed embryo transfer (ET).Retrospective study.Private fertility clinic.Forty-nine women whose embryos had been refrozen after a previous frozen-thawed ET.None.Comparison of implantation and pregnancy rates of twice-cryopreserved, twice-thawed embryos versus once-cryopreserved, once-thawed embryos.The pregnancy rate per ET cycle was 27.8% in the refrozen group and 25.9% in the control group (no statistically significant difference). The implantation rate was 25.0% in the refrozen group and 19.3% in the control group (no statistically significant difference).The refreezing of supernumerary embryos can prevent ovarian hyperstimulation syndrome in stimulated patients and in those who have experienced repeated failed pregnancies. If unexpected supernumerary embryos are available for recryopreservation after frozen-thawed ET, these embryos may be revitrified for a future transfer.