{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T06:42:39Z","timestamp":1772779359076,"version":"3.50.1"},"reference-count":29,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T00:00:00Z","timestamp":1772755200000},"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>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To study the effect of embryo cryopreservation duration on pregnancy and neonatal outcomes in women transferred with high-quality blastocyst during frozen embryo transfer (FET) cycles.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Multicenter Retrospective cohort study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Three tertiary-care academic medical centers.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Patients<\/jats:title>\n                    <jats:p>This retrospective study included a total of 24,101 women who underwent single high-quality blastocyst transfer during their first FET cycles at three tertiary academic medical centers between January 2016 and June 2023.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Intervention(s)<\/jats:title>\n                    <jats:p>Women were categorized into two groups according to the duration of embryo cryopreservation: the short Cryo group consisted of 23,933 women with a storage time of 0\u20135 years, while the long Cryo group included 168 women with a storage time &amp;gt; 5 years. Women in the long Cryo group were matched to those in the short Cryo group using propensity score matching with a 1:4 ratio.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Main outcome measure(s)<\/jats:title>\n                    <jats:p>The pregnancy outcomes and the neonatal outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Result(s)<\/jats:title>\n                    <jats:p>After adjusting for potential confounding factors, no significant differences were observed between the two groups in pregnancy outcomes, including biochemical pregnancy (adjust odds ratio [aOR] 1.04, 95% confidence interval [CI], 0.70\u20131.56; P = 0.831), clinical pregnancy (aOR 1.10, 95% CI, 0.75\u20131.60; P = 0.638), ectopic pregnancy (aOR 2.15, 95% CI, 0.37\u201312.56; P = 0.394), miscarriage (aOR 0.95, 95% CI, 0.54\u20131.69; P = 0.871), and live birth (aOR 1.09, 95% CI, 0.76\u20131.55; P = 0.646). In addition, no significant differences were observed in neonatal outcomes, including very preterm birth, preterm birth, very low birth weight, low birth weight, high birth weight, birth weight, and gestational age.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion(s)<\/jats:title>\n                    <jats:p>Our analysis found no evidence of significant associations between prolonged cryopreservation of high-quality blastocysts and adverse pregnancy or neonatal outcomes.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fendo.2026.1743765","type":"journal-article","created":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T05:30:14Z","timestamp":1772775014000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Cryopreservation duration does not affect pregnancy or neonatal outcomes in single high-quality blastocyst transfers: a multicenter retrospective study"],"prefix":"10.3389","volume":"17","author":[{"given":"Tingting","family":"He","sequence":"first","affiliation":[{"name":"Assisted Reproduction Center, Northwest Women\u2019s and Children\u2019s Hospital","place":["Xi\u2019an, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xia","family":"Xue","sequence":"additional","affiliation":[{"name":"Assisted Reproduction Center, Northwest Women\u2019s and Children\u2019s Hospital","place":["Xi\u2019an, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wei","family":"Li","sequence":"additional","affiliation":[{"name":"Assisted Reproduction Center, Northwest Women\u2019s and Children\u2019s Hospital","place":["Xi\u2019an, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bo","family":"Huang","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xinling","family":"Ren","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bingxin","family":"Ma","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Youzhu","family":"Li","sequence":"additional","affiliation":[{"name":"The Department of Reproductive Medicine, The First Affiliated Hospital of Xiamen University","place":["Xiamen, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lei","family":"Jin","sequence":"additional","affiliation":[{"name":"Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology","place":["Wuhan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juanzi","family":"Shi","sequence":"additional","affiliation":[{"name":"Assisted Reproduction Center, Northwest Women\u2019s and Children\u2019s Hospital","place":["Xi\u2019an, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,6]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1038\/305707a0","article-title":"Human pregnancy following cryopreservation, thawing and transfer of an eight-cell embryo","volume":"305","author":"Trounson","year":"1983","journal-title":"Nature"},{"key":"B2","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1016\/j.repbio.2017.12.004","article-title":"Elective frozen-thawed embryo transfer (FET) in women at risk for ovarian hyperstimulation 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