Prolonged interval time between blastocyst biopsy and vitrification compromised the outcomes in preimplantation genetic testing

Abstract

Summary This study aimed to evaluate to what extent the different interval times between trophectoderm (TE) biopsy and vitrification influence the clinical outcomes in preimplantation genetic testing (PGT) cycles. Patients who underwent frozen embryo transfer (FET) after PGT between 2015 and 2019 were recruited. In total, 297 cycles with single day 5 euploid blastocyst transfer were included. These cycles were divided into three groups according to the interval times: <1 h group, 1–2 h group, and ≥2 h group. Blastocyst survival, clinical pregnancy, miscarriage, and ongoing pregnancy rates were compared. The results showed that, in PGT-SR cycles, survival rate in the ≥2 h group (96.72%) was significantly lower than in the <1 h group (100%, P = 0.047). The clinical pregnancy rate in the ≥2 h group was 55.93%, significantly lower than in the <1 h group (74.26%, P = 0.017). The ongoing pregnancy rates in the 1–2 h group and the ≥2 h group were 48.28% and 47.46%, respectively, significantly lower than that in the <1 h group (67.33%, P < 0.05). The miscarriage rate in the 1–2 h group was 18.42%, significantly higher than that in the <1 h group (5.33%, P = 0.027). In PGT-A cycles, the clinical pregnancy and ongoing pregnancy rates in the <1 h group were 67.44% and 53.49%, respectively, higher than that in the 1–2 h group (52.94%, 47.06%, P > 0.05) and the ≥2 h group (52.63%, 36.84%, P > 0.05). In conclusion, vitrification of blastocysts beyond 1 h after biopsy significantly influences embryo survival and clinical outcomes and is therefore not recommended.

Time from trophectoderm biopsy to vitrification affects the developmental competence of biopsied blastocysts

“…Furthermore, when the blastocysts were cultured for more than 3 h after TE biopsy, the outgrowth area recovered to a level comparable to that of the control and 0‐h biopsy groups. These results suggest that blastocyst vitrification should be performed within 1 h or more than 3 h after TE biopsy 1,9,10 . Secondly, we conducted blastocysts transfer into mice.…”

“…These results suggest that blastocyst vitrification should be performed within 1 h or more than 3 h after TE biopsy. 1 , 9 , 10 Secondly, we conducted blastocysts transfer into mice. Similar to the results of the outgrowth area, the number of pups obtained of 0‐h biopsy and 4‐h biopsy groups was comparable to that of the control group, and the 1‐h biopsy group was significantly lower.…”

“…One such study reported that blastocyst vitrification should be performed 3 or more hours after TE biopsy. 9 However, other groups have reported that the blastocysts should be vitrified immediately or within 1 h after TE biopsy 1 , 10 ; therefore, the optimal timing of vitrification after TE biopsy remains controversial. In the present study, we examined the correlation of different time intervals from TE biopsy to vitrification with blastocyst survival rate and blastocyst outgrowth ability using a mouse model.…”