Successful birth after transfer of vitrified human blastocysts with use of a cryoloop containerless technique.

OBJECTIVE: Clinical application of vitrification for the cryopreservation of human blastocysts.
DESIGN: Clinical trial of vitrification of human blastocysts.
SETTING: Private assisted reproductive technology clinic. PATIENT(S): Supernumerary blastocysts after fresh blastocyst transfer were vitrified for subsequent transfer. INTERVENTION(S): Culture of pronuclear embryos to the blastocyst stage in sequential media and subsequent vitrification of supernumerary blastocysts using a cryoloop technique. MAIN OUTCOME MEASURE(S): Clinical outcome after transfer of vitrified blastocysts. RESULT(S): A total of 60 vitrified blastocysts from 21 patients were warmed, and the survival rate at 2 hours after warming was 63%. Six clinical pregnancies were achieved after 19 transfers. One healthy baby was born, four pregnancies are ongoing, and one ended in miscarriage. CONCLUSION(S): Human blastocysts can be successfully vitrified by suspension on a small nylon loop and a direct plunge into liquid nitrogen. A delivery and ongoing pregnancies prove the safety of this method. This report documents the first successful pregnancy and delivery achieved by blastocyst vitrification using the cryoloop containerless technique.