ArticleFrontiers in endocrinology2021
The Impact of Embryo Storage Time on Pregnancy and Perinatal Outcomes and the Time Limit of Vitrification: A Retrospective Cohort Study.
Article in Frontiers in endocrinology, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 2 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
12 citing papers in PubMed, 2 syntheses or guidelines pooled it, 19 citations in OpenAlex.
- Optimal timing for frozen-thawed embryo transfer: evidence from a systematic review and meta-analysis.Frontiers in endocrinology · 2026Pooled it
- Impact of prolonged embryo storage on reproductive and neonatal outcomes: a systematic review and meta-analysis.Journal of assisted reproduction and genetics · 2024Pooled it
- Does Prolonged Preservation of Blastocysts Affect the Implantation and Live Birth Rate? A Danish Nationwide Register-Based Study.Journal of clinical medicine · 2026Article
- Effect of cryopreservation duration on pregnancy outcomes in embryos: a systematic review and meta-analysis.Human reproduction open · 2026Review
- Impact of post-vitrification storage duration on clinical outcomes of frozen-thawed cleavage-stage embryos transfer: a propensity score-matched retrospective cohort study.Frontiers in endocrinology · 2026Article
- Cryopreservation duration does not affect pregnancy or neonatal outcomes in single high-quality blastocyst transfers: a multicenter retrospective study.Frontiers in endocrinology · 2026Article
- Patient-specific predictors of successful frozen embryo transfer using the freeze-all protocol: a retrospective observational study.Journal of Yeungnam medical science · 2025Article
- Cryopreservation, cryoprotectants, and potential risk of epigenetic alteration.Journal of assisted reproduction and genetics · 2024Review
- Vitrification preservation of good-quality blastocysts for more than 5 years reduces implantation and live birth rates.Human reproduction (Oxford, England) · 2024Article
- Vitrification of human blastocysts for couples undergoing assisted reproduction: an updated review.Frontiers in cell and developmental biology · 2024Review
- Can Cryopreservation in Assisted Reproductive Technology (ART) Induce Epigenetic Changes to Gametes and Embryos?Journal of clinical medicine · 2023Review
- Effect of Long-Term Embryo Cryopreservation on Subsequent Frozen Embryo Transfer Outcomes: A Retrospective Cohort Study.Journal of human reproductive sciencesArticle
Corrections and comments
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Authors and funding
5 authors at 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Background: The technique of embryo cryopreservation has been increasingly applied in clinical settings. However, there has been a concern about the safety and efficacy of long-term freezing of embryos. Therefore, the aim of this study was to evaluate whether storage time of vitrification had any effects on pregnancy as well as perinatal outcomes, further, to explore the appropriate time limit of vitrification. Methods: The study included women who underwent at least one frozen-thawed cycle with single embryo transfer between January 1 Results: A total of 9806 frozen-thawed embryo transfer cycles were included in our study. After adjustment for confounding variables, no significant differences were found in pregnancy outcomes among groups. However, postponement of transfer increased the risks of large for gestational age and placenta previa. In addition, after propensity score matching, 171 cycles with storage time >5 years were matched with those ≤1 year, both the clinical pregnancy rate and live birth rate decreased significantly when the storage time exceeded 5 years. Conclusions: The duration of vitrification did not significantly affect the pregnancy outcomes within 5 years period. However, the clinical pregnancy rate and live birth rate both decreased significantly when the duration of vitrification exceeded 5 years. It is worth noting that the conclusion was drawn from a small sample study after propensity score matching and should be treated with caution. In addition, the cycles were from different time periods, which could have an impact on the results.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.