OBJECTIVE: To present our experience using cocultured cryopreserved and transferred blastocysts. DESIGN: Retrospective study of patients undergoing transfer of cryopreserved blastocysts. SETTING: Three different IVF centers. PATIENTS: Four hundred sixty-seven thawed cycles from January 1991 to June 1994. MAIN OUTCOME MEASURE: Pregnancy rate per cycle after transfer of pre-embryos developed from thawed blastocysts. RESULTS: One thousand two hundred thirty-nine blastocysts were thawed. Of these, 1,033 (83%) survived thawing and were transferred. Five hundred sixty-three thawed cycles resulted in 516 (92%) receiving intrauterine transfer. One hundred twelve clinical pregnancies were established, resulting in a 21.7% pregnancy per transfer with a 19% ongoing rate. The implantation rate of 13.4% results from 138 implanted pre-embryos. There was a higher PR in the programmed cycle (79/302; 26.2%) compared with the natural cycle (6/47;13%). CONCLUSIONS: Freezing at the blastocyst stage is a proven and reliable method in IVF technology. Although there may be fewer pre-embryos, their ability to implant appears to approach the potential of a fresh transfer.
OBJECTIVE: To present our experience using cocultured cryopreserved and transferred blastocysts. DESIGN: Retrospective study of patients undergoing transfer of cryopreserved blastocysts. SETTING: Three different IVF centers. PATIENTS: Four hundred sixty-seven thawed cycles from January 1991 to June 1994. MAIN OUTCOME MEASURE: Pregnancy rate per cycle after transfer of pre-embryos developed from thawed blastocysts. RESULTS: One thousand two hundred thirty-nine blastocysts were thawed. Of these, 1,033 (83%) survived thawing and were transferred. Five hundred sixty-three thawed cycles resulted in 516 (92%) receiving intrauterine transfer. One hundred twelve clinical pregnancies were established, resulting in a 21.7% pregnancy per transfer with a 19% ongoing rate. The implantation rate of 13.4% results from 138 implanted pre-embryos. There was a higher PR in the programmed cycle (79/302; 26.2%) compared with the natural cycle (6/47;13%). CONCLUSIONS: Freezing at the blastocyst stage is a proven and reliable method in IVF technology. Although there may be fewer pre-embryos, their ability to implant appears to approach the potential of a fresh transfer.
Authors: D de Jong; M J C Eijkemans; N G M Beckers; R V Pruijsten; B C J M Fauser; N S Macklon Journal: J Assist Reprod Genet Date: 2002-12 Impact factor: 3.412