Birth of a healthy baby following vitrification of human blastocysts

Objective: To assess vitrification of human blastocysts. Design: Retrospective study of blastocyst vitrification. Setting: A private clinic. Patient(s): Twenty couples with different types of infertility. Intervention(s): Blastocysts were frozen with rapid vitrification and then transferred after thawing. We vitrified blastocysts using a modification of Ishimori's vitrification solution of ethylene glycol and dimethyl sulfoxid e (VSED). Main Outcome Measure(s): After thawing, survival was defined by the embryo' s development morphology after 6 hours or overnight culture. Result(s): Eighteen of 20 patients underwent treatment. Of 45 vitrified bla stocysts, 36 survived, for a survival rate of 80% (36 of 45), The implantat ion rate was 21.9% (7 of 32), and the pregnancy rate (per embryo transfer c ycle) was 33.3% (6 of 18). One of the pregnancies resulted in the delivery of a healthy baby. Conclusion(s): Supernumerary embryos were grown in culture to blastocysts, and the survival rate of vitrified-thawed blastocysts was the same as that for slow freezing of early stage embryos. Blastocyst vitrification should p rove effective for clinical treatment. The present results strongly suggest that this rapid and successful vitrification procedure will replace conven tional cryopreservation in the future. (Fertil Steril(R) 2001;75:1027-9. (C ) 2001 by American Society for Reproductive Medicine.).