Guidance for elective single-embryo transfer should be applied to frozen embryo transfer cycles

Abstract

Purpose To provide clinicians with data showing the benefits of transferring a single blastocyst in frozen embryo transfer (FET) cycles so that they may counsel their patients accordingly. Methods This is a closed cohort study of 678 FET cycles occurring between January 2011 and December 2017 in a private IVF laboratory and associated physicians' practice. Patients included in the analysis were less than 38 years of age at oocyte collection, had at least two vitrified blastocysts, and were undergoing their first autologous FET cycle. The patients were categorized into four groups after they had chosen either elective single-embryo transfer (eSET) or double-embryo transfer (eDET). Outcomes for eSET and eDET were compared within groups of patients having freeze-all IVF cycles (PGT-A patient vs. non-PGT-A patient) and fresh IVF transfer groups (negative outcome vs. pregnant/delivered in fresh cycle). Main outcome measures of the study were live birth, multiple pregnancy, and implantation rates. Results There were no statistically significant differences observed in live birth rates for eSET (54-62%) vs. eDET (54-66%) (P = 0.696-1.000) in the four patient groups evaluated. Multiple pregnancy rates were significantly decreased in all eSET groups (0-3%), compared with eDET groups (24-65%) (P = 0.0001-0.037). Conclusions This data shows that transfer of a single vitrified-warmed blastocyst maintains live birth rates, while decreasing multiple pregnancies, and may become more acceptable to physicians and patients.

D6 blastocyst transfer on day 6 in frozen-thawed cycles should be avoided: a retrospective cohort study

“…Blastocyst transfer facilitates a high pregnancy rate and reduces the incidence of multiple pregnancy and ectopic pregnancy [1][2][3][4][5][6]. Prolonged culture of the embryos to blastocyst stage has become the preferred method in most reproductive centers [5,6].…”

Comparisons of benefits and risks of single embryo transfer versus double embryo transfer: a systematic review and meta-analysis

“…Sixty-two studies [ 11 – 20 , 22 – 24 , 26 – 31 , 38 – 41 , 44 , 45 , 47 – 53 , 56 , 58 , 60 – 62 , 64 – 66 , 69 , 71 , 73 – 75 , 77 – 84 , 86 – 91 , 94 , 99 ] demonstrated a reduced LBR after SET (28,529/85,988, 33.2%) than that after DET (113,658/247,116, 46.0%) in a single cycle (OR = 0.78, 95% CI: 0.71–0.85, I 2 = 91%, P < 0.001) (Supplementary Fig. S1 ).…”

Focus on time-lapse analysis: blastocyst collapse and morphometric assessment as new features of embryo viability

“…Single embryo replacement has presented a challenge to embryologists, who must try to optimize embryo culture and selection in order to maintain an adequate success rate, whilst reducing the overall number of embryos transferred. Indeed, the establishment of more physiological culture media at the end of 1990s has facilitated the culture to the blastocyst stage, aiming to increase the approach of elective single blastocyst transfer (eSBT) [Vega et al, 2018;Freeman et al, 2019;Zilberberg et al, 2021]. This practice allows the selection of embryos at a more advanced stage and increases both uterine and embryonic synchronicity, as well as provides other advantage such as the identification of embryos that have managed to activate their embryonic genome [Braude et al, 1988;Wang and Sun, 2014;Martins et al, 2017;De Vos et al, 2016;Revelli et al, 2019;Ubaldi et al, 2015;De Croo et al, 2020].…”