Successfully healthy baby delivery from human refrozen blastocyst embryos by vitrification

Abstract

To demonstrate delivery by using re-vitrified blastocysts derived from supernumerary embryos in the event of an unsuccessful pregnancy attempt. Nine early stage cleaved embryos were frozen by vitrification, and subsequently thawed. Four of the nine embryos developed to the blastocyst stage. Two of the four blastocysts were transferred, and two supernumerary good embryos remained unexpectedly, and they were refrozen by vitrification under consent. Subsequently, one of the re-vitrified embryos developed to 38 weeks and was delivered by cesarean section (a health female; 46, XX). The transfer of re-vitrified supernumerary blastocysts resulted in a successful pregnancy and delivery outcome. This study suggests that re-vitrification is one rescue procedure which allows the re-use of supernumerary embryos in patients who failed to have a pregnancy after frozen embryo transfer.