{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T15:08:52Z","timestamp":1783091332146,"version":"3.54.6"},"reference-count":42,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T00:00:00Z","timestamp":1775001600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100017959","name":"Health Commission of Hebei Province","doi-asserted-by":"publisher","award":["20240234"],"award-info":[{"award-number":["20240234"]}],"id":[{"id":"10.13039\/100017959","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To develop and validate a predictive model for early blastocyst formation on Day 4 post-fertilization using clinically accessible parameters.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This retrospective cohort of 2,557 patients scheduled for fresh Day 4 embryo transfer was randomly divided into training (n=1,789) and validation (n=768) sets at Xingtai MeiHe Reproductive and Genetic Hospital from January 2021 to December 2025. Early blastocyst formation occurred in 44.9% (training) and 44.1% (validation) of cases. Multivariable logistic regression and nomogram modeling were employed, with model performance assessed via AUC, calibration curves, and decision curve analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>After multivariable adjustment, the number of Day 3 embryos with &amp;gt;10 blastomeres (aOR=1.668, 95% CI: 1.374~2.025, P&amp;lt;0.001) and those with iDAScore &amp;gt;4.8 (aOR=1.369, 95% CI: 1.190 ~ 1.575, P&amp;lt;0.001) were the only independent predictors of Day 4 early blastocyst formation, while 15 covariates including ovarian reserve markers and sperm parameters showed no significant association (P&amp;gt;0.05). The nomogram integrating Day 3 embryos with &amp;gt;10 blastomeres and iDAScore&amp;gt;4.8 demonstrated robust discrimination (training AUC\u00a0=\u00a00.782, 95% CI: 0.738 ~ 0.826; validation AUC\u00a0=\u00a00.773, 95% CI: 0.705 ~ 0.841) with sensitivity of 65.4~65.9% and specificity of 79.6 ~ 81.7%. Calibration curves indicated minimal prediction deviation, and decision curve analysis confirmed clinical net benefits across 18~80% threshold probabilities in the training cohort and 20~93% in the validation cohort. Clinically, early blastocyst formation was associated with superior embryo quality parameters (P&amp;lt;0.001), higher single embryo transfer rates (50.90% vs. 13.96%, P&amp;lt;0.001), and increased clinical (67.65% vs. 59.32%, P&amp;lt;0.001) and ongoing pregnancy rates (59.59% vs. 52.89%, P\u00a0=\u00a00.006), alongside a lower multiple pregnancy rate (22.50% vs. 31.93%, P&amp;lt;0.001). Multivariable regression confirmed early blastocyst formation as an independent predictor of pregnancy success (clinical pregnancy aOR=1.675, 95% CI: 1.287 ~ 2.180, P&amp;lt;0.001; ongoing pregnancy aOR=1.612, 95% CI: 1.249 ~ 2.080, P&amp;lt;0.001).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The validated nomogram accurately predicts Day 4 early blastocyst formation using Day 3 embryo parameters. The presence of early blastocyst formation on Day 4 might indicate suitability for selective Day 4 embryo transfer.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fendo.2026.1752963","type":"journal-article","created":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T04:46:32Z","timestamp":1775018792000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Development and validation of a predictive model for early blastocyst formation on day 4 post-fertilization"],"prefix":"10.3389","volume":"17","author":[{"given":"Yasong","family":"Geng","sequence":"first","affiliation":[{"name":"Xingtai Key Laboratory of Reproductive Medicine, Xingtai Meihe Reproductive and Genetic Hospital","place":["Xingtai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fangfang","family":"Dai","sequence":"additional","affiliation":[{"name":"Xingtai Key Laboratory of Reproductive Medicine, Xingtai Meihe Reproductive and Genetic Hospital","place":["Xingtai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haoyang","family":"Dai","sequence":"additional","affiliation":[{"name":"Xingtai Key Laboratory of Reproductive Medicine, Xingtai Meihe Reproductive and Genetic Hospital","place":["Xingtai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linlin","family":"Tao","sequence":"additional","affiliation":[{"name":"Xingtai Key Laboratory of Reproductive Medicine, Xingtai Meihe Reproductive and Genetic Hospital","place":["Xingtai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jing","family":"Ma","sequence":"additional","affiliation":[{"name":"Hebei Key Laboratory of Reproductive Medicine, Hebei Reproductive Health Hospital","place":["Shijiazhuang, Hebei, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiayi","family":"Yin","sequence":"additional","affiliation":[{"name":"Institute of Biology, Hebei Academy of Sciences","place":["Shijiazhuang, Hebei, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Zheng","sequence":"additional","affiliation":[{"name":"Xingtai Key Laboratory of Reproductive Medicine, Xingtai Meihe Reproductive and Genetic Hospital","place":["Xingtai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,4,1]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejogrb.2005.08.022","article-title":"Extended embryo culture reduces the implantation rate on day 4 and day 5 when only a maximum of three embryos are cultured beyond the pronuclear stage","volume":"124","author":"Montag","year":"2006","journal-title":"Eur J Obstet Gynecol Reprod Biol"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1007\/BF02211726","article-title":"Relationship between the day of embryo transfer and the outcome in human in vitro fertilization and embryo transfer","volume":"11","author":"Goto","year":"1994","journal-title":"J Assist Reprod Genet"},{"key":"B3","doi-asserted-by":"publisher","first-page":"37","DOI":"10.1186\/s12958-017-0253-6","article-title":"Pregnancy rates of day 4 and day 5 embryos after culture in an integrated time-lapse incubator","volume":"15","author":"Holschbach","year":"2017","journal-title":"Reprod Biol Endocrinol"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1016\/s0015-0282(99)00458-6","article-title":"Implantation rates after in vitro fertilization and transfer of a maximum of two embryos that have undergone three to five days of culture","volume":"73","author":"Huisman","year":"2000","journal-title":"Fertil Steril"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1016\/j.fertnstert.2016.06.029","article-title":"Cleavage-stage or blastocyst transfer: what are the benefits and harms","volume":"106","author":"Glujovsky","year":"2016","journal-title":"Fertil Steril"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1002\/14651858.CD002118.pub5","article-title":"Cleavage stage versus blastocyst stage embryo transfer in assisted reproductive technology","volume":"6","author":"Glujovsky","year":"2016","journal-title":"Cochrane Database Syst Rev"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1016\/j.rbmo.2012.07.008","article-title":"Comparable clinical outcomes and live births after single vitrified-warmed and fresh blastocyst transfer","volume":"25","author":"Feng","year":"2012","journal-title":"Reprod BioMed Online"},{"key":"B8","doi-asserted-by":"publisher","first-page":"1996","DOI":"10.1093\/humrep\/deq145","article-title":"Transfer of a selected single blastocyst optimizes the chance of a healthy term baby: a retrospective population based study in Australia 2004-2007","volume":"25","author":"Wang","year":"2010","journal-title":"Hum Reprod"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-017-1092-2","article-title":"No advantage of fresh blastocyst versus cleavage stage embryo transfer in women under the age of 39: a randomized controlled study","volume":"35","author":"Levi-Setti","year":"2018","journal-title":"J Assist Reprod Genet"},{"key":"B10","doi-asserted-by":"publisher","first-page":"123","DOI":"10.31083\/j.ceog5105123","article-title":"Comparison of Clinical Outcomes between the Fourth Day and the Fifth Day Embryo Transfer in IVF\/ICSI Cycles: A Retrospective Cohort Study before and after PSM","volume":"51","author":"Geng","year":"2024","journal-title":"Clin Exp Obstet Gynecol"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1016\/j.tjog.2017.12.008","article-title":"Day 4 good morula embryo transfer provided compatible live birth rate with day 5 blastocyst embryo in fresh IVF\/ET cycles","volume":"57","author":"Li","year":"2018","journal-title":"Taiwan J Obstet Gynecol"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1093\/humupd\/4.4.440","article-title":"Uterine junctional zone contractions during assisted reproduction cycles","volume":"4","author":"Lesny","year":"1998","journal-title":"Hum Reprod Update"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/17.6.1513","article-title":"The neglected morula\/compact stage embryo transfer","volume":"17","author":"Tao","year":"2002","journal-title":"Hum Reprod"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.3389\/fcell.2021.746104","article-title":"Assisted hatching treatment of piezo-mediated small hole on zona pellucida in morula stage embryos improves embryo implantation and litter size in mice","volume":"9","author":"Hao","year":"2021","journal-title":"Front Cell Dev Biol"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-019-01475-0","article-title":"Should the flexibility enabled by performing a day-4 embryo transfer remain as a valid option in the IVF laboratory? A systematic review and network meta-analysis","volume":"36","author":"Simopoulou","year":"2019","journal-title":"J Assist Reprod Genet"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.12659\/MSM.928737","article-title":"Comparison of pregnancy outcomes between single-morula embryo transfer and single-blastocyst transfer in fresh IVF\/ICSI cycles","volume":"27","author":"Zhang","year":"2021","journal-title":"Med Sci Monit"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.3760\/cma.j.cn101441-20230511-00194","article-title":"Comparison of clinical outcomes and maternal and fetal outcomes between day 4 and day 5 embryo transfer in fresh cycle","volume":"44","author":"Tao","year":"2024","journal-title":"Chin J Reprod Contrac"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1017\/S0967199424000212","article-title":"The TLI system can help day-3 single cleavage embryo transfer to obtain comparative clinical outcomes to day-4 or day-5","volume":"32","author":"Ji","year":"2024","journal-title":"Zygote"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.1186\/s12958-023-01059-9","article-title":"The presence of partial compaction patterns is associated with lower rates of blastocyst formation, sub-optimal morphokinetic parameters and poorer morphologic grade","volume":"21","author":"Hur","year":"2023","journal-title":"Reprod Biol Endocrinol"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deaf021","article-title":"The Istanbul consensus update: a revised ESHRE\/ALPHA consensus on oocyte and embryo static and dynamic morphological assessment\u2020,\u2021","volume":"40","author":"Coticchio","year":"2025","journal-title":"Hum Reprod"},{"key":"B21","doi-asserted-by":"publisher","first-page":"458","DOI":"10.1186\/s12884-024-06597-7","article-title":"Comparison of pregnancy outcomes between 4th day morula and 5th day blastocyst after embryo transfer: a retrospective cohort study","volume":"24","author":"Sun","year":"2024","journal-title":"BMC Preg Childb"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deab011","article-title":"Perturbations of morphogenesis at the compaction stage affect blastocyst implantation and live birth rates","volume":"36","author":"Coticchio","year":"2021","journal-title":"Hum Reprod"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/16.9.1970","article-title":"The Graduated Embryo Score (GES) predicts blastocyst formation and pregnancy rate from cleavage-stage embryos","volume":"16","author":"Fisch","year":"2001","journal-title":"Hum Reprod"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2024.1432943","article-title":"Development and validation of a clinical prediction model for blastocyst formation during IVF\/ICSI-ET","volume":"15","author":"Liu","year":"2024","journal-title":"Front Endocrinol (Laus)"},{"key":"B25","doi-asserted-by":"publisher","first-page":"55","DOI":"10.5935\/1518-0557.20190054","article-title":"The KidscoreTM D5 algorithm as an additional tool to morphological assessment and PGT-A in embryo selection: a time-lapse study","volume":"24","author":"Gazzo","year":"2020","journal-title":"JBRA Assist Reprod"},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.1017\/S0967199422000016","article-title":"The KIDScore\u2122 D3 scoring system contributes to the prediction of embryonic development potential: A promising tool for screening high-quality embryos","volume":"30","author":"Zhou","year":"2022","journal-title":"ZYGOTE"},{"key":"B27","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1186\/s12958-024-01198-7","article-title":"Assessment of artificial intelligence model and manual morphokinetic annotation system as embryo grading methods for successful live birth prediction: a retrospective monocentric study","volume":"22","author":"Papamentzelopoulou","year":"2024","journal-title":"Reprod Biol Endocrinol"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-022-02562-5","article-title":"Correlation between an annotation-free embryo scoring system based on deep learning and live birth\/neonatal outcomes after single vitrified-warmed blastocyst transfer: a single-centre, large-cohort retrospective study","volume":"39","author":"Ueno","year":"2022","journal-title":"J Assist Reprod Genet"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1186\/s12958-024-01185-y","article-title":"Associations between the artificial intelligence scoring system and live birth outcomes in preimplantation genetic testing for aneuploidy cycles","volume":"22","author":"Lee","year":"2024","journal-title":"Reprod Biol Endocrinol"},{"key":"B30","doi-asserted-by":"publisher","first-page":"981","DOI":"10.3390\/genes16080981","article-title":"Deep learning models: their relationship with embryonic euploidies and reproductive outcomes","volume":"16","author":"Selntigia","year":"2025","journal-title":"Genes"},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0262661","article-title":"Robust and generalizable embryo selection based on artificial intelligence and time-lapse image sequences","volume":"17","author":"Berntsen","year":"2022","journal-title":"PloS One"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.1186\/s12958-024-01230-w","article-title":"Enhancing clinical utility: deep learning-based embryo scoring model for non-invasive aneuploidy prediction","volume":"22","author":"Ma","year":"2024","journal-title":"Reprod Biol Endocrinol"},{"key":"B33","doi-asserted-by":"publisher","DOI":"10.3390\/biomedicines13071734","article-title":"Predictive ability of an objective and time-saving blastocyst scoring model on live birth","volume":"13","author":"Ma","year":"2025","journal-title":"Biomedicines"},{"key":"B34","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1093\/humrep\/deu295","article-title":"Which set of embryo variables is most predictive for live birth? A prospective study in 6252 single embryo transfers to construct an embryo score for the ranking and selection of embryos","volume":"30","author":"Rhenman","year":"2015","journal-title":"Hum Reprod"},{"key":"B35","doi-asserted-by":"publisher","DOI":"10.1016\/j.rbmo.2021.05.002","article-title":"Evaluation of artificial intelligence using time-lapse images of IVF embryos to predict live birth","volume":"43","author":"Sawada","year":"2021","journal-title":"Reprod BioMed Online"},{"key":"B36","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2024.1449035","article-title":"Can time-lapse culture combined with artificial intelligence improve ongoing pregnancy rates in fresh transfer cycles of single cleavage stage embryos","volume":"15","author":"Wang","year":"2024","journal-title":"Front Endocrinol (Laus)"},{"key":"B37","doi-asserted-by":"publisher","first-page":"775","DOI":"10.1186\/s12884-024-06976-0","article-title":"Effect of day 3 embryo cell number on the pregnancy and neonatal outcomes of day 4 single embryo transfer from fresh cycles","volume":"24","author":"Tao","year":"2024","journal-title":"BMC Preg Childb"},{"key":"B38","doi-asserted-by":"publisher","first-page":"1067","DOI":"10.1186\/s40001-025-03343-3","article-title":"Effect of day 3 cell number on the pregnancy and neonatal outcomes of vitrified-warmed single blastocyst transfer","volume":"30","author":"Tao","year":"2025","journal-title":"Eur J Med Res"},{"key":"B39","doi-asserted-by":"publisher","DOI":"10.1080\/01443615.2019.1676212","article-title":"Predictors of blastocyst formation rate in elective day 5 transfer cycle","volume":"40","author":"Hong","year":"2020","journal-title":"J Obstet Gynaecol"},{"key":"B40","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2025.1496803","article-title":"Effects of trigger-day progesterone in c-IVF\/ICSI cycles on blastocyst culture outcomes","volume":"16","author":"Sun","year":"2025","journal-title":"Front Endocrinol (Laus)"},{"key":"B41","doi-asserted-by":"publisher","DOI":"10.1177\/0300060513485910","article-title":"Pregnancy outcomes of day 5 embryo transfer in patients at high risk of developing ovarian hyperstimulation syndrome and analysis of factors affecting blastocyst formation","volume":"41","author":"Xin","year":"2013","journal-title":"J Int Med Res"},{"key":"B42","doi-asserted-by":"publisher","first-page":"24511","DOI":"10.1038\/s41598-025-10298-2","article-title":"Prediction of blastocyst development using cleavage-stage embryo metrics and maternal age","volume":"15","author":"Ji","year":"2025","journal-title":"Sci Rep"}],"container-title":["Frontiers in Endocrinology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fendo.2026.1752963\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T04:46:36Z","timestamp":1775018796000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fendo.2026.1752963\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,1]]},"references-count":42,"alternative-id":["10.3389\/fendo.2026.1752963"],"URL":"https:\/\/doi.org\/10.3389\/fendo.2026.1752963","relation":{},"ISSN":["1664-2392"],"issn-type":[{"value":"1664-2392","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,1]]},"article-number":"1752963"}}