{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,16]],"date-time":"2026-05-16T12:17:00Z","timestamp":1778933820957,"version":"3.51.4"},"reference-count":28,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,10,18]],"date-time":"2021-10-18T00:00:00Z","timestamp":1634515200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec><jats:title>Objective<\/jats:title><jats:p>This prospective randomized controlled trial compared the reproductive outcomes of frozen embryo transfer (FET) with hormone replacement treatment (HRT) with or without gonadotropin-releasing hormone agonist (GnRHa) pretreatment.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A total of 133 patients scheduled for HRT-FET mainly because of tubal and\/or male factors who received two high-quality cleavage-stage embryos were enrolled at two participating centers. The GnRHa group (<jats:italic>n<\/jats:italic> = 65) received GnRHa pretreatment, while the control group (<jats:italic>n<\/jats:italic> = 68) did not. Analysis was based on the intention-to-treat (ITT) principle.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Among the 133 participants, 130 (97.7%) underwent embryo transfer and 127 (95.5%) completed the protocol. The clinical pregnancy rate according to ITT did not differ between the GnRHa and control groups [39\/65 (60.0%) <jats:italic>vs<\/jats:italic>. 41\/68 (60.3%), <jats:italic>p<\/jats:italic> = 0.887]. The implantation rate (47.6% <jats:italic>vs<\/jats:italic>. 45.3%, <jats:italic>p<\/jats:italic> = 0.713), early pregnancy loss rate (5.1% <jats:italic>vs<\/jats:italic>. 19.5%, <jats:italic>p<\/jats:italic> = 0.09), and live birth rate (49.2% <jats:italic>vs<\/jats:italic>. 50.0%, <jats:italic>p<\/jats:italic> = 0.920) were also comparable between groups.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Pretreatment with GnRHa does not improve the reproductive outcomes for women receiving HRT-FET.<\/jats:p><\/jats:sec><jats:sec><jats:title>Clinical Trial Registration<\/jats:title><jats:p>The study was registered with the Chinese Clinical Trial Registry (ChiCTR-IOR-17014170; <jats:ext-link>http:\/\/www.chictr.org.cn<\/jats:ext-link>).<\/jats:p><\/jats:sec>","DOI":"10.3389\/fendo.2021.722253","type":"journal-article","created":{"date-parts":[[2021,10,20]],"date-time":"2021-10-20T19:38:03Z","timestamp":1634758683000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":23,"title":["Endometrial Preparation for Frozen\u2013Thawed Embryo Transfer With or Without Pretreatment With GnRH Agonist: A Randomized Controlled Trial at Two Centers"],"prefix":"10.3389","volume":"12","author":[{"given":"Jian","family":"Xu","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shu-Zhen","family":"Li","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Min-Na","family":"Yin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pei-Ling","family":"Liang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ping","family":"Li","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ling","family":"Sun","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2021,10,18]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dev339","article-title":"A Fresh Look at the Freeze-All Protocol: A SWOT Analysis","volume":"31","author":"Blockeel","year":"2016","journal-title":"Hum Reprod"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dep042","article-title":"Elective Single Embryo Transfer With Cryopreservation Improves the Outcome and Diminishes the Costs O F IVF\/ICSI","volume":"24","author":"Veleva","year":"2009","journal-title":"Hum Reprod"},{"key":"B3","doi-asserted-by":"publisher","first-page":"330","DOI":"10.1016\/j.fertnstert.2017.10.019","article-title":"Pregnancy-Related Complications and Perinatal Outcomes Resulting From Transfer of Cryopreserved Versus Fresh Embryos In Vitro Fertilization: A Meta-Analysis","volume":"109","author":"Sha","year":"2018","journal-title":"Fertil Steril"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dex285","article-title":"Frozen Embryo Transfer: A Review on the Optimal Endometrial Preparation and Timing","volume":"32","author":"Mackens","year":"2017","journal-title":"Hum Reprod"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1007\/s10815-016-0736-y","article-title":"The Endometrial Preparation for Frozen-Thawed Euploid Blastocyst Transfer: A Prospective Randomized Trial Comparing Clinical Results From Natural Modified Cycle and Exogenous Hormone Stimulation With G nRH Agonist","volume":"33","author":"Greco","year":"2016","journal-title":"J\u00a0Assist Reprod Genet"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1016\/S0015-0282(02)04132-8","article-title":"Comparing the Effects of GnRH-A on Endometrial Receptivity in Patients Undergoing ART and Prepared Frozen Embryo Transfer Cycles","volume":"78","author":"Taskin","year":"2002","journal-title":"Fertil Steril - 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