Laser-assisted hatching improves clinical outcomes of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos: a prospective randomized study

How to improve the implantation rate and clinical outcomes of embryo transfers in patients following IVF is a hot issue in current studies of human assisted reproduction technology. In this study, we aimed to evaluate the effects of quarter zona-pellucida opening by laser assisted hatching (QLAH) on the clinical outcomes following the transfer of vitrified-warmed blastocysts developed from low-grade cleavage-stage embryos in patients with all their high-grade and fair-grade cleavage-stage embryos transferred but who had not become pregnant. Our results showed that the implantation and clinical pregnancy rates were significantly increased after QLAH, suggesting that QLAH may serve as a potential approach for effectively utilizing low-grade cleavage-stage embryos, which are often discarded) and increasing the chances of pregnancy in patients undergoing IVF. However, further multicentre studies on a larger scale should be performed.