Effect of artificial shrinkage on clinical outcome in fresh blastocyst transfer cycles

Abstract

ObjectiveThis study aimed to determine the safety and clinical effect of artificial shrinkage (AS) in terms of assisted hatching of fresh blastocysts. Also, we evaluated the correlation between patient age and the effect of AS on clinical outcome.MethodsTwo AS methods, using a 29-gauge needle and laser pulse, were compared. Seventy-three blastocysts were shrunk using a 29-gauge needle and the same number of other blastocysts were shrunk by a laser pulse. We evaluated the shrunken blastocysts hourly and considered them viable if they re-expanded >70%. Blastocyst transfer cycles (n=134) were divided into two groups: a control group consisted of the cycles whose intact embryos were transferred (n=100), while the AS group consisted of the cycles whose embryos were replaced following AS (n=34). The implantation and pregnancy rates of the control group and AS group were compared (p<0.05).ResultsThe re-expansion rates of the 29-gauge needle and laser pulse AS groups were similar (56 [76.7%] vs. 62 [84.9%], respectively). All of the remaining shrunken blastocysts were re-expanded within 2 hours. There was no degeneration of shrunken blastocysts. The total and clinical pregnancy rate of the AS group (23 [67.6%]; 20 [58.8%], respectively) was significantly higher than that of the control group (47 [47.0%]; 39 [39.0%], respectively). In the older patient group, there was no difference in the clinical outcomes between the AS and control groups.ConclusionThese results suggest that AS of blastocoele cavity, followed by the transfer, would be a useful approach to improve the clinical outcome in cycles in which fresh blastocyst stage embryos are transferred.

Vitrification of blastocysts at various degrees of blastocoele expansion using different exposure times to the equilibration solution

“…Contrary to what we saw in this study, several authors found that survival rates, and subsequent implantation and birth rates were higher when the degree of blastocoele expansion was high and when an artificial collapse of the blastocoele cavity was induced before vitrification 13,29,[31][32][33] . Blastocoele collapse can be achieved mechanically by aspiring the blastocoele liquid with a micropipette or by inducing a releasing of this liquid using a laser shot 22,34 . Several studies have shown that high-quality early blastocyst embryos (G1 and G2) do not systematically develop to viable fully expanded blastocyst able to hatch and implant 29,32,35 .…”

Blastocoele re‐expansion time in vitrified–warmed cycles is a strong predictor of clinical pregnancy outcome

“…Several factors can influence blastocyst re‐expansion, including vitrification technology and embryonic parameters. The AS technique is considered an effective method to restore the blastocoele and improve the efficiency of vitrification and clinical pregnancy rates . Desai et al .…”

Short-term storage of tripronucleated human embryos

“…In the case of blastocysts, TPN embryos were transferred on day 3 of development from IVF-20 TM drops to CCM TM (Scandinavian IVF, EMB, Barcelona, Spain) drops and cultured in the aforementioned conditions for three additional days. On day 6 of development, 62 TPN-derived hatched blastocysts were selected and their blastocoel artificially shrunken by a laser pulse [22,23,33] before being assigned at random to one of the three storage periods (0 h, 24 h or 48 h).…”