Abstract: Assisted reproductive technology which brings hope to infertility patients, but also brings the risk for multiple pregnancy. To solve the low pregnancy rate and the problems of multiple births in IVF/ICSI（In vitro fertilization/Intracyto-plasmic sperm injection） cycle, reproductive medicine specialists have been searching for the balance. Many reproductive center found that elective single embryo transfer, can reduce multiple births and still keep high clinical pregnancy rate. Elective single embtyo transfer is the development trend of assisted reproductive technology currently for the patients who have the high risk of multiple births.

Key words: Fertilization, in vitro, Elective single embryo transfer, Embryo transfer, Ｐregnancy, multiple, Pregnancy rate