Prediction of Embryo Implantation Rate Using a Sole Parameter of Timing of Starting Blastulation

Elena Soukhov, Gilad Karavani, Irit Szaingurten-Solodkin, Samira Alfayumi-Zeadna, Guy Elharar, Dganit Richter, Tamar Wainstock, Atif Zeadna, Eliahu Levitas, Iris Har-Vardi

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


A time-lapse monitoring system provides a complete picture of the dynamic embryonic development process and simultaneously supplies extensive morphokinetic data. The objective of this study was to investigate whether the use of the morphokinetic parameter of time of starting blastulation (tSB) can improve the implantation rate of day-5 transferred blastocyst selected based on morphological parameters. In this retrospective study we analyzed the morphokinetics of 196 day-5 transferred blastocysts, selected solely based on morphological parameters. The interval time from intracytoplasmic sperm injection (ICSI) to time of starting blastocyst formation (tSB) was calculated for each embryo. The overall implantation rate of transferred blastocyst, selected based only on morphological parameters, was 49.2%. Implantation rate, determined retrospectively, was significantly higher (58.8% versus 42.6%, P = 0.02) for embryos with a short interval time to tSB (78-95.9 h) compared with embryos with a longer timeframe (96-114 h). Time of expanded blastocyst (tEB) post-ICSI was also significantly associated with implantation; however, this parameter was not available for all the embryos at time of transfer. When we tested only high ranked KIDScore day-3 sub-group embryos, the implantation rate was significantly higher in short interval time embryos compared with longer interval time embryos (62.2% vs. 45.5%, respectively, P = 0.02).These observations emphasize the importance of the timing of starting blastulation over blastocyst morphological parameters and may provide a preferable criterion for good morphology day-5 blastocyst selection.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
StatePublished - 18 Feb 2022


  • Blastocyst
  • Embryo selection
  • KIDScore
  • Morphokinetics
  • Starting time of blastulation

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology


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