Effects of removal of necrotic blastomeres from human cryopreserved embryos on pregnancy outcome

This study assessed whether the implantation potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres. We retrospectively analyzed the pregnancy rate and implantation rate of 170 human frozen embryo transfer cycles. Laser-assisted hatching and micromanipulation were performed to remove the necrotic blastomeres. A higher clinical pregnancy rate (22.22%) and embryo implantation rate (10.17%) were observed when transferred embryos comprised fully intact and partially damaged embryos compared with partially damaged embryos alone (5.88% and 2.82%, respectively). When transferred embryos were fully intact and partially damaged embryos, removal of necrotic blastomeres from partially damaged embryos significantly increased the clinical pregnancy rate (43.90% versus 24.00%, P<0.05) and the implantation rate (19.44% versus 10.29%, P<0.05). The results indicated that the implantation potential of partially damaged cryopreserved embryos can be improved by removal of necrotic blastomeres with laser-assisted hatching and micromanipulation.