The impact of M-phase on blastocyst development: a time-lapse study

ObjectiveTo determine the key morphokinectic parameters on blastulation using a time-lapse monitoring system (TMS).DesignRetrospective observational cohort study.Materials and MethodsPatients were treated at the Reproductive Medicine Center of Tongji Hospital from 2013 to 2014. A total of 1,038 embryos were enrolled by using TMS, and all patients gave written informed consent. All patients in this study underwent routine IVF-ET clinical and laboratory treatment at the center, and no additional intervention was performed. All embryos in this study were cultured to day 6 and assigned into two groups: formed available blastocyst group (FAB, n=380) and unformed available blastocyst group (UAB, n=658). The precise timing of cell division and developmental parameters were determined: time of extrusion of second polar body (2pb), time of PN appearance (PNA) and fading (PNF), time of cleavage to two-blastomere embryo (t2), t3-t8. Additionally, the time duration of events were also calculated: PNA-PNF, PNF-t2 (M-phase), cc2 (t3-t2), s2 (t4-t2), cc3 (t5-t4), s3 (t8-t5).ResultsThe time of PNF, t2 and t4 among FAB embryos were significantly (p<0.001) lower than those of UAB embryos. In contrast, the time of t5 among FAB embryos were significantly (p<0.001) higher than those of UAB embryos. In addition, all of the time duration of events were significantly different between the two groups. However, to assess which morphokinectic paremeter affected blastocyst development, multivariate logistic regression was performed. The result showed that only PNF-t2 was significantly related to blastulation (P < 0.001).ConclusionsThe time duration of M-phase was linked successfully to blastocyst development. ObjectiveTo determine the key morphokinectic parameters on blastulation using a time-lapse monitoring system (TMS). To determine the key morphokinectic parameters on blastulation using a time-lapse monitoring system (TMS). DesignRetrospective observational cohort study. Retrospective observational cohort study. Materials and MethodsPatients were treated at the Reproductive Medicine Center of Tongji Hospital from 2013 to 2014. A total of 1,038 embryos were enrolled by using TMS, and all patients gave written informed consent. All patients in this study underwent routine IVF-ET clinical and laboratory treatment at the center, and no additional intervention was performed. All embryos in this study were cultured to day 6 and assigned into two groups: formed available blastocyst group (FAB, n=380) and unformed available blastocyst group (UAB, n=658). The precise timing of cell division and developmental parameters were determined: time of extrusion of second polar body (2pb), time of PN appearance (PNA) and fading (PNF), time of cleavage to two-blastomere embryo (t2), t3-t8. Additionally, the time duration of events were also calculated: PNA-PNF, PNF-t2 (M-phase), cc2 (t3-t2), s2 (t4-t2), cc3 (t5-t4), s3 (t8-t5). Patients were treated at the Reproductive Medicine Center of Tongji Hospital from 2013 to 2014. A total of 1,038 embryos were enrolled by using TMS, and all patients gave written informed consent. All patients in this study underwent routine IVF-ET clinical and laboratory treatment at the center, and no additional intervention was performed. All embryos in this study were cultured to day 6 and assigned into two groups: formed available blastocyst group (FAB, n=380) and unformed available blastocyst group (UAB, n=658). The precise timing of cell division and developmental parameters were determined: time of extrusion of second polar body (2pb), time of PN appearance (PNA) and fading (PNF), time of cleavage to two-blastomere embryo (t2), t3-t8. Additionally, the time duration of events were also calculated: PNA-PNF, PNF-t2 (M-phase), cc2 (t3-t2), s2 (t4-t2), cc3 (t5-t4), s3 (t8-t5). ResultsThe time of PNF, t2 and t4 among FAB embryos were significantly (p<0.001) lower than those of UAB embryos. In contrast, the time of t5 among FAB embryos were significantly (p<0.001) higher than those of UAB embryos. In addition, all of the time duration of events were significantly different between the two groups. However, to assess which morphokinectic paremeter affected blastocyst development, multivariate logistic regression was performed. The result showed that only PNF-t2 was significantly related to blastulation (P < 0.001). The time of PNF, t2 and t4 among FAB embryos were significantly (p<0.001) lower than those of UAB embryos. In contrast, the time of t5 among FAB embryos were significantly (p<0.001) higher than those of UAB embryos. In addition, all of the time duration of events were significantly different between the two groups. However, to assess which morphokinectic paremeter affected blastocyst development, multivariate logistic regression was performed. The result showed that only PNF-t2 was significantly related to blastulation (P < 0.001). ConclusionsThe time duration of M-phase was linked successfully to blastocyst development. The time duration of M-phase was linked successfully to blastocyst development.