The Impact of Age on Gestation and Implantation Rates and on Blastocyst Scoring, after Single and Double Embryo Transfers

Successful single embryo transfer (SET) cycles depend primarily on the choice of the best embryo to be transferred. Recent study on single blastocyst transfers has shown that trophectoderm (TE) quality is the most important parameter for successful pregnancy and live birth. Patient´s age however, is a key component of a woman´s reproductive potential. The present retrospective study aimed to analyze first the effect of maternal age on clinical gestation and implantation rates after single and double blastocyst transfers. Second, patients were divided into two age groups (<35 and >35 years old) and their blastocyst scores were recorded after single or double (DET) transfers resulting in single or twin pregnancy or non-pregnancy. Our data clearly shows that for young women (<35 years of age) the transfer of a single blastocyst results in similar gestational rates as DETs, without the risk of twin pregnancies. In addition, our data show that for both young and older women TE score is the most important parameter to be assessed for embryo selection. In addition, inner cell mass (ICM) plays an important role in blastocyst selection in older (>35 years of age) patients. We suggest that blastocyst grading for patients aged 35 years or above shall be performed using a strict grading policy, possibly not of a single parameter, but TE, ICM and expansion grades together to choose the “best combined-score blastocyst” and DETs should be considered, particularly after previous cycles with pregnancy failures.