Effect of the site of assisted hatching on vitrified-warmed blastocyst transfer cycles: a prospective randomized study

Abstract

Purpose To assess the effect of assisted hatching (AH) site on the clinical outcomes in vitrified-warmed blastocyst transfer cycles. Methods A total of 160 women who underwent vitrifiedwarmed blastocyst transfer cycles were randomized to either the ICM group (AH performing at the site near the inner cell mess, ICM), or the TE group (AH performing at the site opposite to the ICM). AH with laser zona drilling was performed 20 or 30 min after thawing once the ICM can be detected. Clinical pregnancy rate, implantation rate, live birth rate and the occurrence rate of monozygotic twins (MZT) pregnancy after transfer of these two groups were compared. Results No significant difference was found in the clinical pregnancy rate (63.8 % vs. 67.5 %), implantation rate (51.7 % vs. 53.6 %) and live birth rate (57.5 % vs. 62.5 %) between the ICM group and the TE group. The occurrence rate of MZT was comparable between the two groups (3.9 % vs. 5.6 %). Conclusions The site of assisted hatching has no influence on the implantation, pregnancy and live birth rate in human vitrified-warmed blastocyst transfer cycles.

Blastocyst hatching site is regularly distributed and does not influence foetal development in mice

“…Some researchers performing AH at a site close to the ICM observed a higher rate of complete hatching in human vitrified blastocysts 8 . Interestingly, further study found the AH site had no influence on implantation, clinical pregnancy, or live birth rate 11 . Others found the site of AH did not influence the rate of completed hatching by blastocysts in mice 9 .…”

“…Although these two hatching patterns were both observed in IVF and ICSI embryos, they have no effect on embryo implantation. In human vitrified-warmed blastocysts, the assisted hatching (AH) site (near or opposite to the ICM) did not affect blastocyst implantation or subsequent pregnancy and live birth rates 11 . Conversely, others found that ZP opening close to the ICM was associated with a higher implantation and pregnancy rate in humans 12 .…”

Assisted Hatching for In Vitro Fertilization-Embryo Transfer: An Update

“…LAH was performed within 20-30 min after blastocyst thaw once the ICM was detected. There was no difference in IR, PR, LBR, or monozyogotic twin rate between the two groups [9].…”

Effect of Total versus Partial Assisted Hatching on the Clinical Pregnancy Rates in Assisted Reproduction Technology

“…Following introduction of the best technique to be laser AH, studies started to investigate the partial or total zona hatching on the ART outcome (23)(24)(25)(26). Additional studies on the frozen-thawed embryo cycles revealed variable results (27,28). Age also has been an issue, and assessed in several further studies to determine whether there is an optimal age group, who would benefit from AH, again these studies showed variable results (29)(30)(31).…”