Cumulative live birth rate after fresh elective single blastocyst transfer and subsequent frozen single blastocyst transfer compared to initial fresh double blastocysts transfer in women aged 40-43 years.
*BLASTOCYST *BIRTH rate *FERTILIZATION in vitro *FROZEN human embryos *CRYOPRESERVATION of organs, tissues, etc. *LOGISTIC regression analysis *TRANSPLANTATION of organs, tissues, etc.