关键词: 胚胎移植, 妊娠, 多胎, 生殖技术, 辅助, 受精, 体外

Abstract: As the great advances in ART，the rate of clinical pregnancy has been gradually improved，while the rate of multiple pregnancies, especially 逸3 pregnancies, was at very high level. The probability ofadverse pregnancy outcomes significantly increases in multiple pregnancies. Recently，patients undergoing IVFwould like to implant more embryos due to the expectation of high pregnant rate and low expense of their own.However，the risks and benefits always coexist in clinical practice. To optimize the outcome of IVF，the risks must be minimized if the clinical pregnancy rate is not significantly affected. In addition，blindness exists in embryo selection. It is important to set upa personalized strategy of embryo transplantation for those differentIVF patients. For normal responders with over 6 good-quality embryos，the blastocyst transfer can obtain ideal clinical pregnancies with decreased multiple pregnancy rate. For patients without obtained good -quality embryos，good clinical outcome can be acquired using blastocyst transfer. Assisted hatching （AH）can markedly improve the clinical pregnancies of those elderly patients. For high responders，freezing-thawing embryo transfer （FET）may bea better choice.

Key words: Embryotransfer, Pregnancy, multiple, Reproductivetechniques, assisted, FertilizationinVitro