Prevalence, consequence, and significance of reverse cleavage by human embryos viewed with the use of the Embryoscope time-lapse video system

Blastocyst collapse is not an independent predictor of reduced live birth: a time-lapse study

“…In addition to these morphokinetic variables other studies (11)(12)(13)(14)(15)(16) focused on qualitative markers of cleavage-stage embryos that were associated with a reduced implantation potential and could be used as deselection criteria such as direct cleavage, multinucleation, and abnormal cleavage patterns. In a recently published study (17) another negative prognostic marker emerged, but in a blastocyst-stage embryo.…”

Timing of Embryo Cleavage

“…Reverse cleavage type 2 (incomplete): zygote or blastomere fails to separate (type I, Supplemental Video 1; type 2, Supplemental Videos 2 are available online at www.fertstert.org). It could occur up to three times in 27.4% of embryos during the first three cleavage cycles [12]. They found GnRH antagonist protocol and ICSI procedure had higher incidence of reverse cleavage compared with GnRH agonist protocol and IVF procedure.…”

Assessment of human embryos by time-lapse videography: A comparison of quantitative and qualitative measures between two independent laboratories

“…Embryos with 2-or 4-cell stages <5 h were classified as direct cleavage (DC) [8,10], and excluded from morphokinetic comparison. Reverse cleavage (RC), which was also excluded from morphokinetic comparison, was defined as either (a) two daughter blastomeres re-combining after complete separation following cleavage division, or (b) failed cytokinesis following the disappearance and reappearance of the nucleus [9]. The degree of cell contact observed between blastomeres was also assessed at the end of the 4-cell stage by recording the number of intercellular cell count points (ICCPs) [8].…”

“…Time-lapse videography permits continuous monitoring of human embryo growth over the entire culture period to assess both quantitative morphokinetic measures [1][2][3][4][5][6][7] and the occurrence of qualitative indicators of atypical cleavage [7][8][9][10][11]. The use of enclosed incubators equipped with built-in video cameras does not appear to be detrimental to embryo quality [12], possibly improving culture conditions [13], and may be advantageous in improving clinical pregnancy rates [4,14] although further high quality evidence is required before routine application [15,16].…”