How to improve the pregnancy outcome by optimizing embryo cryopreservation protocol / 天津医药

ABSTRACT

Objective To investigate how to optimize the protocol of embryo cryopreservation to improve the success of frozen-thawed embryo transfer (FET), reduce multiple pregnancy rate and increase the cumulative pregnancy rate from one oocyte retrieval process. Methods The clinical data of 1 166 FET cycles were retrospectively analyzed and separated into different groups445 for vitrification and 721 for slow-freezing. The vitrification group was divided into single embryo (28 cy?cles), double embryos (71 cycles) and triple embryos (346 cycles). 0-1 optimal embryo was called O0-1 group (235 cycles), 2 optimal embryos were called O2 group (80 cycles), 3 optimal embryos were called O3 group (130 cycles). The difference preg?nancy outcomes (implantation rate, clinical pregnancy, abortion rate and live-birth rate) were compared between groups. Results (1) There were significantly higher embryo survival rate(98.3%vs 73.1%), embryo recovery rate without damaging (83.3%vs 62.1%), implantation rate(36.8%vs 29.9%), clinical pregnancy(57.1%vs 44.0%) and live-birth rate(47.9%vs 34.5%) in vitrification group than those of slow freezing group(P0.05). Conclusion Vitrification technology can improve the clinical pregnancy and live-birth rate, and decrease multiple preg?nancy rate. Two optimal embryos in one tube are supposed to be the preferred method for embryo cryopreservation.