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.

To evaluate whether the developmental potential of embryos that were partially damaged after freezing and thawing can be improved by removal of necrotic blastomeres. Eight-cell mouse embryos were cryopreserved using 1,2-propanediol and sucrose as cryoprotectant with slow cooling procedure. After thawing, blastocyst formation and hatching of fully intact embryos were compared between no treatment and with laser-assisted hatching. For partially intact embryos, the effects of removal of necrotic blastomeres with micromanipulation were evaluated. Laser-assisted hatching of mouse cryopreserved fully intact embryos significantly increased blastocyst hatching (63.4% versus 48.3%, P<0.05), but had little effect on blastocyst formation (72.0% versus 70.1%, P>0.05). The removal of necrotic blastomeres from partially damaged mouse cryopreserved embryos with micromanipulation significantly increased blastocyst formation (52.9% versus 32.0%, P<0.05) and blastocyst hatching (41.2% versus 22.0%, P>0.05) compared with the control group. The developmental potential of partially damaged cryopreserved embryos can be improved by removal of necrotic blastomeres with micromanipulation.