Fragment removal of the fragmented human day2 embryos significantly increased subsequent development and clinical outcomes

The purpose of this study was to assess the beneficial effect of fragment removal on the subsequent development and pregnancy outcome of the fragmented human day 2 embryos. The study included 96 patients who underwent day 3 ET program from March 2015 to October 2015. The patients were divided into two groups; Fragment removal (FR) group (n=48) and control group (n=48). There were no differences between the FR and the control groups in the number of blastomeres (4.0±1.3 vs. 4.0±1.3) and the morphological grade of embryos (3.1±0.6 vs. 3.1±0.5) before fragment removal on day 2. Fragment removal was performed on the grade 3 embryos (10 %< degree of fragmentation <25%) of the FR group. We performed assisted hatching with laser and fragments removal on day 2. Before fragment removal, the fragmented embryos were incubated in G-PGD medium (Vitrolife) under paraffin oil (Ovoil, Vitrolife) for 30 minutes. Microsurgical fragment removal was performed with handmade suction micro-pipet with outer diameter of 30μm. There were no differences in the characteristics of the patients between the FR and the control groups; mean age of the patients (36.2±4.3 vs. 36.2±4.1), endometrial thickness (10.4±2.5 vs. 10.0±2.0), AMH levels (4.4±4.5 vs. 4.2±2.9), and mean number of retrieved oocytes (8.7±5.7 vs. 9.2±4.8). No differences were also observed between the two groups in fertilization rate (76.0±17 vs. 71.0±22%) and mean number of ET (2.0±0.4 vs. 2.0±0.3). After fragment removal and 24 h culture in vitro, although the number of blastomeres (7.0±1.6 vs. 6.8±1.6) was comparable in the two groups, embryo morphological grade (2.0±0.8) of the FR group was significantly improved compared to that (3.2±0.5 p<0.01) of the control group. Clinical pregnancy (43.8%) and implantation rates (28.1%) of the FR group were significantly higher than the rates (23.0 and 14.7%, respectively, P<0.05) of the control group. Early fragment removal on day 2 significantly improved the subsequent development and pregnancy outcomes of the fragmented embryos. These results suggest that early fragment removal effectively prevents secondary degeneration of fragmented embryos by eliminating the release of toxic substances as soon as possible.