ArticleBMC pregnancy and childbirth2020
D6 blastocyst transfer on day 6 in frozen-thawed cycles should be avoided: a retrospective cohort study.
Article in BMC pregnancy and childbirth, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers.
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Who cites it
10 citing papers in PubMed.
- Interaction between progesterone exposure duration and blastocyst expansion stage on live birth following frozen-thawed transfer of day-6 blastocysts.Frontiers in endocrinology · 2026Article
- Effect of progesterone timing on live birth rates in day-6 blastocyst frozen-thawed embryo transfer cycles: a randomized controlled trial.Human reproduction open · 2026Article
- Associations of mixed exposure to ambient air pollution and environmental factors with the risk of miscarriage in women undergoing assisted reproductive technology: a retrospective cohort study.BMC public health · 2025Article
- Day 6 vitrified blastocyst transfer on day 5 vs. day 6 of progesterone shows similar outcomes in HRT-FET cycles: a cohort study.Scientific reports · 2025Article
- The Impact of Embryo Quality on Pregnancy Outcomes in Single Day 5 versus Day 6 Euploid Blastocyst Transfer: A Retrospective Cohort Study.International journal of fertility & sterility · 2024Article
- Association Between Pregnancy Outcomes and the Time of Progesterone Exposure of D6 Single-Blastocyst Transfer in Frozen-Thawed Cycles: A Retrospective Cohort Study.International journal of women's health · 2024Article
- Novel Time-Lapse Parameters Correlate with Embryo Ploidy and Suggest an Improvement in Non-Invasive Embryo Selection.Journal of clinical medicine · 2023Article
- The pregnancy outcomes of day-5 poor-quality and day-6 high-quality blastocysts in single blastocyst transfer cycles.Clinical and experimental reproductive medicine · 2023Article
- Comparison of clinical outcomes of frozen-thawed D5 and D6 blastocysts undergoing preimplantation genetic testing.Journal of translational medicine · 2022Article
- Increased risk of abortion after frozen-thawed embryo transfer in women with polycystic ovary syndrome phenotypes A and D.Scientific reports · 2022Article
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6 authors.
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Abstract
backgroundThere is no definitive evidence about the suitable timing to transfer blastocysts formed and cryopreserved on day 6 (D6 blastocysts) in frozen-thawed embryo transfer (FET) cycles. This study aimed to investigate the suitable timing to transfer D6 blastocysts in FET cycles and to identify factors affecting clinical pregnancy rate (CPR) and early miscarriage rate (EMR) in FET cycles with blastocysts.
methodsThis retrospective cohort study included 1788 FET cycles with blastocysts. There were 518 cycles with D6 blastocysts, and 1270 cycles with blastocysts formed and cryopreserved on day 5 (D5 blastocysts) (D5 group). According to the blastocyst transfer timing, the cycles with D6 blastocysts were divided into cycles with D6 blastocysts transferred on day 5 (D6-on-D5 group, 103 cycles) and cycles with D6 blastocysts transferred on day 6 (D6-on-D6 group, 415 cycles). The chi-square test, independent t-test or Mann-Whitney test, and logistic regression analysis were used for data analysis.
resultsThe CPR and implantation rate (IR) were significantly higher in the D6-on-D5 group than in the D6-on-D6 group (55.3% vs. 37.3%, 44.8% vs. 32.6%, P < 0.01). The CPR and IR were significantly higher in the D5 group than in the D6-on-D5 group (66.0% vs. 55.3%, 62.1% vs. 44.8%, P < 0.05), and the EMR was significantly lower in the D5 group than in the D6-on-D5 group (11.2% vs. 21.1%, P < 0.05). Logistic regression analysis demonstrated that transfer D6 blastocysts on day 5, instead of day 6, could significantly increase the CPR (odds ratio[OR]: 2.031, 95% confidence interval (CI): 1.296-3.182, P = 0.002). FET cycles with D6 blastocysts transferred on day 5 had a higher EMR than those with D5 blastocysts (OR: 2.165, 95% CI: 1.040-4.506, P = 0.039). Hormone replacement therapy (HRT) cycles exhibited a higher EMR than natural cycles (OR: 1.953, 95% CI: 1.254-3.043, P = 0.003), while no difference was observed in the CPR (P > 0.05).
conclusionsThese results indicate that the suitable timing to transfer D6 blastocysts in FET cycles may be day 5, and D6 blastocyst transfer on day 6 in FET cycles should be avoided. D6 blastocysts transfer and HRT cycles may be associated with a higher EMR.
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