Should embryos developing to blastocysts on day 7 be cryopreserved and transferred: an analysis of pregnancy and implantation rates

Kovalevsky, G.; Carney, S.M.; Morrison, L.S.; Boylan, C.F.; Neithardt, Adrienne B.; Feinberg, Ronald F.

doi:10.1016/j.fertnstert.2013.06.021

Cited by 57 publications

(54 citation statements)

References 18 publications

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“…The final inclusion was 13 studies that met the selection criteria for our meta‐analysis. Hence, 23 studies were included in the following meta‐analyses . The main characteristics and assessment for risk of bias of the included studies are presented in Table .…”

Section: Resultsmentioning

confidence: 99%

“…The widespread application of blastocysts transfer has helped us to confirm that day 6 blastocyst formation is, in reality, a relatively frequent event. It is estimated that this phenomenon occurs in 30% of blastocyst cultivation . Given the high frequency of day 6 blastocyst formation, understanding the pregnancy outcomes of day 6 BET becomes clinically important.…”

Section: Introductionmentioning

confidence: 99%

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Pregnancy outcomes after day 5 versus day 6 blastocyst‐stage embryo transfer: A systematic review and meta‐analysis

Wang²,

Sun

et al. 2020

J of Obstet and Gynaecol

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Aim To compare the pregnancy outcomes after day 5 blastocyst‐stage embryo transfers (BET) versus day 6 BET following vitrified‐warmed cycle and to evaluate whether the number of embryos transferred and the chromosomal status of embryo influence effect estimates. Methods A literature search (PubMed, Embase and MEDLINE) up to January 2019 was conducted to identify studies where women with day 6 BET were compared to women with day 5 BET. Only studies published in English language, on peer‐reviewed journal were considered eligible. The following subgroup analyses were performed: (i) number of embryos transferred and (ii) chromosomal status of embryo. Results From a total of 1956 articles identified, 23 observational studies were included in the meta‐analysis. We observed that day 6 BET were associated with lower implantation rate (risk ratio, RR: 1.17, 95% confidence interval, CI: 1.10–1.24), clinical pregnancy rate (RR: 1.17, 95% CI: 1.10–1.24), ongoing pregnancy rate (RR: 1.15, 95% CI: 1.07–1.24) and live birth rate (RR: 1.22, 95% CI: 1.11–1.33) than day 5 BET following vitrified‐warmed cycle. The subgroup analysis found that the superiority of day 5 BET compared with day 6 BET is influenced by the number of embryos transferred and chromosomal status of embryos. Conclusion Current evidence shows that day 5 BET is superior to day 6 BET following vitrified‐warmed cycle in clinical practice. Due to the overall low quality of available evidence, more larger and well‐conducted studies are needed to compare the pregnancy outcomes between day 5 and day 6 BET before drawing a clear conclusion.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pregnancy outcomes after day 5 versus day 6 blastocyst‐stage embryo transfer: A systematic review and meta‐analysis

Wang²,

Sun

et al. 2020

J of Obstet and Gynaecol

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“…Many studies have shown that the chromosomal status of embryo may affect the embryo cleavage rate and morphology [18,23,24]. Most of the researchers used fluorescence in situ hybridization (FISH) techniques and found a higher incidence of chromosomal abnormality of cleavage-stage embryos with poor morphology.…”

Section: Discussionmentioning

confidence: 99%

The clinical outcomes of day 3 4-cell embryos after extended in vitro culture

Zhao

Lian

et al. 2014

J Assist Reprod Genet

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Objective To evaluate the development potential and clinical significance of day 3 4-cell embryos after extended in vitro culture. Methods This study was a retrospective cohort study for patients with infertility treatment between January 2011 and July 2013. Patients undergoing blastocyst culture in controlled ovarian hyperstimulation cycles using surplus embryos were analyzed in the study. A total of 764 women undergoing blastocyst culture with 1,522 surplus 4-cell embryos on day 3 were analyzed. An additional 2,391 patients with embryos undergoing blastocyst culture during the same period with embryos having more blastomeres were chosen as control. Results After extended culture, 253 embryos from 183 cycles in the study group which developed to blastocysts were frozen, and 118 embryos were warmed in subsequent frozen embryo transfer cycles. Implantation rates, clinical pregnancy rates (PRs) and ongoing PRs were 33.3 %, 38.4 % and 31.4 %, respectively, which were similar to those of the control group. The singleton birth weights of newborns using these blastocysts showed no significant difference to that seen in the control group. Conclusion Surplus 4-cell embryos on day 3 displayed lower blastulation rates. However, once a blastocyst is obtained, it has equivalent clinical outcomes. Embryos that are developmentally lagging on day 3 can be observed in extended culture to increase the cumulative chances of a successful pregnancy.

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“…ongoing pregnancy rates of the D5 blastocyst were significantly higher than those of blastocysts in the D6 and D7 groups [6]. Similarly, the results of the study by Liebermann et al also suggested that the pregnancy outcome of D5 was better than that of the D6 blastocyst [8].…”

Section: Discussionmentioning

confidence: 83%

“…Our center used vitrification freezing to freeze the embryos, which was based on the previously described [6]. The blastocysts were subjected to artificial shrinkage before being frozen, and then allowed to equilibrate for 2 min in a pre-equilibrated solution containing 7.5% (v/v) dimethylsulfoxide (DMSO) and 7.5% (v/v) ethylene glycol (EG), followed by transfer to a vitrification freezing solution-15% (v/v) DMSO + 15% (v/v) EG + 0.65 mol/l sucrose + 10 mg/ml Ficoll-where the blastocysts were allowed to equilibrate for 30 s. Subsequently, the blastocysts were transferred to a Cryoloop, which was then preserved in liquid nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Comparison of Pregnancy Outcomes of High-Quality D5- and D6-Blastocyst Transfer in Hormone-Replacement Frozen-Thawed Cycles

Xing¹,

Cai²,

Sun³

et al. 2017

IJCM

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This study aimed to assess pregnancy outcomes after high-quality D5-and D6-blastocyst transfer in frozen cycles of in vitro fertilization and embryo transfer and to further evaluate whether there was a difference in blastocyst development potentials with different developmental speeds and in pregnancy outcomes. A retrospective analysis was conducted to analyze 247 frozen cycles in our center from September 2015 to July 2017, which were divided into two groups: a D5-FET group with 193 cycles of D5-blastocyst transfer, and a D6-FET group with 54 cycles of D6-blastocyst transfer. Hormone replacement method was utilized to prepare frozen-cycle endometria. Pregnancy outcomes were analyzed and compared between these two groups. The mean ages of the two groups were 31.45 ± 4.43 years and 31.98 ± 4.84 years, respectively, with no statistically significant differences (P > 0.05). The difference in the endometrial thickness during transfer was also not statistically significant. The implantation rate in the D5-FET group was 60.13%, significantly higher than that in the D6-FET group (31.58%, P < 0.05). The clinical pregnancy rate in the D5-FET group was 68.91%, significantly higher than that in the D6-FET group (40.74%, P < 0.05). No statistically significant differences were found in the abortion rate and ectopic pregnancy rate between the two groups. The implantation, biochemical pregnancy, and clinical pregnancy rates of the blastocyst D5 were all superior to those of the blastocyst D6. In clinics, therefore, D5-blastocyst transfer could be prioritized for embryo transfer.

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Should embryos developing to blastocysts on day 7 be cryopreserved and transferred: an analysis of pregnancy and implantation rates

Cited by 57 publications

References 18 publications

Pregnancy outcomes after day 5 versus day 6 blastocyst‐stage embryo transfer: A systematic review and meta‐analysis

Pregnancy outcomes after day 5 versus day 6 blastocyst‐stage embryo transfer: A systematic review and meta‐analysis

The clinical outcomes of day 3 4-cell embryos after extended in vitro culture

Comparison of Pregnancy Outcomes of High-Quality D5- and D6-Blastocyst Transfer in Hormone-Replacement Frozen-Thawed Cycles

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