Evidence map›Paper›PMID 41268807›Full record

SynthesisActa obstetricia et gynecologica Scandinavica2026

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

Wenhui Hou, Ziyi Wang, Tianrui Wen, Yuanlin Ma, Manman Lu, Xiuli Fan, Feifei Zhao

Abstract readSystematic ReviewMeta-Analysis
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Acta obstetricia et gynecologica Scandinavica, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Wenhui HouReproductive Medical Center, Henan Province Key Laboratory for Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.ORCID 0000-0002-6226-6555
Ziyi WangReproductive Medical Center, Henan Province Key Laboratory for Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
Tianrui WenReproductive Medicine Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.
Yuanlin MaReproductive Medicine Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.
Manman LuReproductive Medical Center, Henan Province Key Laboratory for Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
Xiuli FanObstetric Department, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
Feifei ZhaoReproductive Medical Center, Henan Province Key Laboratory for Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.

Funding

Henan Provincial Science and Technology Research Project LHGJ20200317National Natural Science Foundation of China 82101744
6 · The paper itself

Abstract

introductionEmbryo transfer at the blastocyst stage has become popular in assisted reproductive technology, but it is still a challenge for embryologists to select the embryos with the highest implantation potential. We aimed to investigate whether blastocyst development speed and blastocyst quality affect pregnancy and perinatal outcomes in single frozen-thawed blastocyst transfer (SFBT) cycles. MATERIAL AND

methodsWe therefore conducted a meta-analysis to compare the pregnancy and perinatal outcomes after day 5 versus day 6 SFBT. Pregnancy and perinatal outcomes of SFBT included HCG positive rate, clinical pregnancy rate (CPR), live birth rate (LBR), miscarriage rate (MR), multiple pregnancy rate (MPR), ongoing pregnancy rate (OPR), ectopic pregnancy rate (EPR), mean birth weight, low birth weight (LBW) rate, rate of macrosomia, mean gestational age at birth, preterm birth rate, birth defects rate, and sex ratio (female/male).

resultsA total of 106 316 participants were included in this meta-analysis and were assigned to the D5 (n = 66 329) and D6 (n = 39 987) SFBT groups. Pooled analysis showed that the D5 SFBT group had a higher HCG positive rate (RR 1.24, 95% CI 1.14-1.34), CPR (RR 1.28, 95% CI 1.22-1.34), OPR (RR 1.36, 95% CI 1.21-1.53), LBR (RR 1.39, 95% CI 1.32-1.47), and a lower MR (RR 0.78, 95% CI 0.73-0.83) than the D6 SFBT group. No significant difference was observed between the D5 and D6 SFBT groups in other pregnancy and perinatal outcomes. Subgroup analysis comparing poor-quality D5 blastocysts with high-quality D6 blastocysts revealed no significant differences in most outcomes, except for a lower HCG positive rate (RR 0.92, 95% CI 0.87-0.97) and a higher rate of macrosomia (RR 2.13, 95% CI 1.05-4.31) in the poor-quality D5 group.

conclusionsThe findings suggested that transfer D5 blastocysts should be prioritized over D6 blastocysts in SFBT in clinical practice. Besides, poor-quality D5 blastocysts and D6 high-quality blastocysts exhibited comparable outcomes. Given the overall low quality of available evidence, the association between the pregnancy outcomes and blastocyst development speed requires further investigation.

Indexed as

Embryo TransferPregnancy OutcomeFemaleHumansInfant, NewbornPregnancyPregnancy Rateday5 versus day6perinatal outcomespregnancy outcomessingle frozen–thawed blastocyst transfer

Identifiers

PMID41268807
PMCPMC12746211

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Registered trials

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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.