Synchrony of the first division as an index of the blastocyst formation rate during embryonic development

Mizobe, Yamato; Tokunaga, Makoto; Oya, Naoto; Iwakiri, Reiko; Yoshida, Naomi; Sato, Yumi; Onoue, Nanase; Ezono, Yuji

doi:10.1002/rmb2.12070

Cited by 13 publications

(7 citation statements)

References 32 publications

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“…In our study, t2 (first cleavage), ECC1 (duration of the cell cycle) and t4 (third cleavage) occurred significantly earlier in the ASCC group compared to the NSCC group. Published data indicate that a precocious first cleavage (t2 < 25.9 h) is predictive of blastulation [33,34], embryonic quality on day 3 post-fertilization [35] and a better implantation rate [25,33]. The t4 seems to be associated with the formation of a good-quality blastocyst [33] and a better implantation rate [19,25,33] in favor of early onset.…”

Section: Discussionmentioning

confidence: 99%

Sperm Chromatin Condensation Defect Accelerates the Kinetics of Early Embryonic Development but Does Not Modify ICSI Outcome

Jumeau

Rives

Lechevallier

et al. 2022

IJMS

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The origin and quality of gametes are likely to influence the kinetics of embryonic development. The purpose of the study was to assess the impact of sperm nuclear quality, and in particular sperm chromatin condensation, on the kinetics of early embryo development after intracytoplasmic sperm injection (ICSI). Our study included 157 couples who benefitted from ICSI for male factor infertility. Chromatin condensation and DNA fragmentation were assessed in spermatozoa prior to ICSI. Above the 20% threshold of sperm condensation defect, patients were included in the abnormal sperm chromatin condensation (ASCC) group; below the 20% threshold, patients were included in the normal sperm chromatin condensation (NSCC) group. After ICSI, the oocytes were placed in the time-lapse incubator. The kinetics of the cohort’s embryonic development have been modeled. The fading times of pronuclei and the time to two blastomeres (t2, first cleavage) and four blastomeres (t4, third cleavage) differed significantly between the NSCC and ASCC groups, with earlier events occurring in the ASCC group. On the other hand, the state of sperm chromatin condensation did not seem to have an impact on live birth rates or the occurrence of miscarriages. The kinetics of early embryonic development was accelerated in males with a sperm chromatin condensation defect without compromising the chances of pregnancy or promoting miscarriage. However, our study highlights the paternal contribution to early embryonic events and potentially to the future health of the conceptus.

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Section: Discussionmentioning

confidence: 99%

Sperm Chromatin Condensation Defect Accelerates the Kinetics of Early Embryonic Development but Does Not Modify ICSI Outcome

Jumeau

Rives

Lechevallier

et al. 2022

IJMS

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“…One possibility is a delay in the time to 2 cells (t2), the other possibility is that t2 is normal, but the duration of the second cell cycle (cc2) was prolonged. In the rst case, early cleavage has become an established developmental competence biomarker in standard morphology selection schemes [24].The timing and synchronicity of the rst division are useful assessments for determining blastocyst formation rate [25,26]. Observation via time-lapse imaging (TLI) has revealed lower implantation and live birth potential for embryos that undergo cleavage after 30 hours (t2>30hrs).…”

Section: Discussionmentioning

confidence: 99%

Embryos undergoing delayed second mitosis exhibit a reduced blastocyst formation rate and a lower live birth even if third mitosis was completed on time

Dong,

Ma,

et al. 2023

Preprint

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Background: The phenomenon of day3 (D3) 8-cell embryos derived from day2 (D2) 2-cell embryos can occur in in vitro fertilization (IVF) laboratories. Abnormal cleavage patterns can predict delayed second mitosis. Here, we investigated the developmental potential of these embryos to provide a reference for the selection of embryos for transplantation. Methods: Embryos were divided into four groups according to cell number on D2 and D3. Group A featured high-quality D2 2-cell embryos that developed into high-quality D3 8-cell embryos; group B featured the same type of embryos as group A except the embryos developed to compaction; group C featured high-quality D2 4-cell embryos that developed into D3 8-cell high quality embryos and group D featured the same type of embryos as group C except the embryos developed to compaction. Results: The blastocyst formation rate of group A and group B was significantly lower than that of group C (P<0.001). With regards to D3 single embryo transfer (SET) and frozen single blastocyst transfer (SBT), the clinical pregnancy and live birth rates of group A were comparable with those of group C. For D3 double-embryo transfer (DET), the biochemical pregnancy rate, clinical pregnancy rate, and live birth rate, following the combined transfer of embryos from group A and Group C was significantly lower than that when transferring two embryos from group C. Conclusions: Embryos with delayed second mitosis exhibited a lower blastocyst formation rate and poorer embryo outcomes even though third mitosis was completed on time. Blastocyst culture is useful for selecting blastocysts with a higher probability of live birth for embryos with delayed second mitosis. Trial registration: This study is retrospective and does not require trial registration.

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“…In our study, using time-lapse monitoring, the latest incidence of first cleavage was recorded at 39 hpi, but blastocysts did not develop from embryos that cleaved later than 27 hpi. In humans, two-cell embryos that cleave at 25–28 hpi are usually selected for transfer to improve the chance of achieving pregnancy [ 30 , 31 , 32 ].…”

Section: Discussionmentioning

confidence: 99%

“…We observed a large synchronization of the first division for early embryos (22–23 hpi) and the majority of the best quality embryos cleaved at 22(±39 min) hpi. In humans, it was found that the blastocyst formation rate was significantly increased in the high-synchrony (first division synchrony ±3.96 h) compared with the low-synchrony groups (first division synchrony longer than 3.96 h) [ 31 ]. Further cell divisions were not synchronous and embryos dividing t2–t3 at 8–15 h after the first cleavage had the highest development rates [ 31 ].…”

Section: Discussionmentioning

confidence: 99%

“…In humans, it was found that the blastocyst formation rate was significantly increased in the high-synchrony (first division synchrony ±3.96 h) compared with the low-synchrony groups (first division synchrony longer than 3.96 h) [ 31 ]. Further cell divisions were not synchronous and embryos dividing t2–t3 at 8–15 h after the first cleavage had the highest development rates [ 31 ]. In humans, it has been established that the duration of the cell cycle is around 10 to 12 h [ 32 ].…”

Section: Discussionmentioning

confidence: 99%

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Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

Kochan

Nowak

Kij

et al. 2021

Animals

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The aim of this study was to analyze the morphokinetic parameters of feline embryos using a time lapse system. Oocytes matured in vitro were fertilized (IVF) and in vitro cultured in a time lapse-system (Primo Vision®, Gothenburg, Sweden). The first cell division of embryos occurred between 17 h post insemination (hpi) and 38 hpi, with the highest proportion of embryos (46%) cleaving between 21 and 24 hpi. The timing of the first cleavage significantly affected further embryo development, with the highest development occurring in embryos that cleaved at 21–22 hpi. Embryos that cleaved very early (17–18 hpi) developed poorly to the blastocyst stage (2%) and none of the embryos that cleaved later than 27 hpi were able to reach the blastocyst stage. Morphological defects were observed in 48% of the embryos. There were no statistically significant differences between the timing intervals of the first cleavage division and the frequency of morphological defects in embryos. Multiple (MUL) morphological defects were detected in more than half (56%) of the abnormal embryos. The most frequent single morphological defects were cytoplasmic fragmentation (FR) (8%) and blastomere asymmetry (AS) (6%). Direct cleavage (DC) from 1–3 or 3–5 blastomeres, reverse cleavage (RC) and vacuoles were rarely observed (2–3%). The timing of blastocyst cavity formation is a very good indicator of embryo quality. In our study, blastocyst cavity formation occurred between 127–167 hpi, with the highest frequency of hatching observed in blastocysts that cavitated between 142–150 hpi. Blastocysts in which cavitation began after 161 h did not hatch. In conclusion, the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

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Synchrony of the first division as an index of the blastocyst formation rate during embryonic development

Cited by 13 publications

References 32 publications

Sperm Chromatin Condensation Defect Accelerates the Kinetics of Early Embryonic Development but Does Not Modify ICSI Outcome

Sperm Chromatin Condensation Defect Accelerates the Kinetics of Early Embryonic Development but Does Not Modify ICSI Outcome

Embryos undergoing delayed second mitosis exhibit a reduced blastocyst formation rate and a lower live birth even if third mitosis was completed on time

Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

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