{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T14:54:03Z","timestamp":1789829643611,"version":"4.0.1"},"reference-count":45,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"13","license":[{"start":{"date-parts":[[2024,3,29]],"date-time":"2024-03-29T00:00:00Z","timestamp":1711670400000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2024,3,29]]},"abstract":"<jats:p>\n                    In this retrospective study conducted at Sichuan Jinxin Xinan Women and Children\u2019s Hospital spanning January 2015 to December 2021, our objective was to investigate the impact of embryo cryopreservation duration on outcomes in frozen embryo transfer. Participants, totaling 47,006 cycles, were classified into 3 groups based on cryopreservation duration: \u22641 year (Group 1), 1 to 6 years (Group 2), and\u2005\u22656 years (Group 3). Employing various statistical analyses, including 1-way ANOVA, Kruskal\u2013Wallis test, chi-square test, and a generalized estimating equation model, we rigorously adjusted for confounding factors. Primary outcomes encompassed clinical pregnancy rate and Live Birth Rate (LBR), while secondary outcomes included biochemical pregnancy rate, multiple pregnancy rate, ectopic pregnancy rate, early and late miscarriage rates, preterm birth rate, neonatal birth weight, weeks at birth, and newborn sex. Patient distribution across cryopreservation duration groups was as follows: Group 1 (40,461 cycles), Group 2 (6337 cycles), and Group 3 (208 cycles). Postcontrolling for confounding factors, Group 1 exhibited a decreased likelihood of achieving biochemical pregnancy rate, clinical pregnancy rate, and LBR (OR\u2005&lt;\u20051, aOR\u2005&lt;\u20051,\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    \u2005&lt;\u2005.05). Furthermore, an elevated incidence of ectopic pregnancy was observed (OR\u2005&gt;\u20051, aOR\u2005&gt;\u20051), notably significant after 6 years of freezing time [aOR\u2005=\u20054.141, 95% confidence intervals (1.013\u201316.921),\n                    <jats:italic toggle=\"yes\">P<\/jats:italic>\n                    \u2005=\u2005.05]. Cryopreservation exceeding 1 year was associated with an increased risk of early miscarriage and preterm birth (OR\u2005&gt;\u20051, aOR\u2005&gt;\u20051). No statistically significant differences were observed in birth weight or sex between groups. However, male infant birth rates were consistently higher than those of female infants across all groups. In conclusion, favorable pregnancy outcomes align with embryo cryopreservation durations within 1 year, while freezing for more than 1 year may diminish clinical pregnancy and LBRs, concurrently elevating the risk of ectopic pregnancy and preterm birth.\n                  <\/jats:p>","DOI":"10.1097\/md.0000000000037542","type":"journal-article","created":{"date-parts":[[2024,3,29]],"date-time":"2024-03-29T14:02:04Z","timestamp":1711720924000},"page":"e37542","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":7,"title":["Study on the optimal time limit of frozen embryo transfer and the effect of a long-term frozen embryo on pregnancy outcome"],"prefix":"10.1097","volume":"103","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6803-7318","authenticated-orcid":false,"given":"Xue-Jiao","family":"Wang","sequence":"first","affiliation":[{"name":"Sichuan Jinxin Xinan Women and Children\u2019s Hospital, Chengdu, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ming-Xing","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Women and Children\u2019s Hospital of Chongqing Medical University, Chongqing, China"},{"name":"Joint International Research Laboratory of Reproduction and Development of the Ministry of Education of China, School of Public Health, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ling-Ling","family":"Ruan","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Women and Children\u2019s Hospital of Chongqing Medical University, Chongqing, China"},{"name":"Joint International Research Laboratory of Reproduction and Development of the Ministry of Education of China, School of Public Health, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Tan","sequence":"additional","affiliation":[{"name":"Sichuan Jinxin Xinan Women and Children\u2019s Hospital, Chengdu, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li-Hong","family":"Geng","sequence":"additional","affiliation":[{"name":"Sichuan Jinxin Xinan Women and Children\u2019s Hospital, Chengdu, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hui-Jun","family":"Yang","sequence":"additional","affiliation":[{"name":"Assisted Reproductive Center, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li-Juan","family":"Fu","sequence":"additional","affiliation":[{"name":"Joint International Research Laboratory of Reproduction and Development of the Ministry of Education of China, School of Public Health, Chongqing Medical University, Chongqing, China"},{"name":"Department of Pharmacology, Academician Workstation, Changsha Medical University, Changsha, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhao-Hui","family":"Zhong","sequence":"additional","affiliation":[{"name":"Joint International Research Laboratory of Reproduction and Development of the Ministry of Education of China, School of Public Health, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xing-Yu","family":"Lv","sequence":"additional","affiliation":[{"name":"Sichuan Jinxin Xinan Women and Children\u2019s Hospital, Chengdu, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Bin","family":"Ding","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Women and Children\u2019s Hospital of Chongqing Medical University, Chongqing, China"},{"name":"Joint International Research Laboratory of Reproduction and Development of the Ministry of Education of China, School of Public Health, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6978-4777","authenticated-orcid":false,"given":"Qi","family":"Wan","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, West China Second Hospital, Sichuan University, Chengdu, China"},{"name":"Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, China."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"R1-20250503","doi-asserted-by":"crossref","first-page":"67","DOI":"10.3389\/fendo.2020.00067","article-title":"The future of cryopreservation in assisted reproductive technologies.","volume":"11","author":"Bosch","year":"2020","journal-title":"Front Endocrinol (Lausanne)"},{"key":"R2-20250503","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1093\/humupd\/dmz037","article-title":"Ovarian stimulation for freeze-all IVF cycles: a systematic review.","volume":"26","author":"Mizrachi","year":"2020","journal-title":"Hum Reprod Update"},{"key":"R3-20250503","first-page":"CD011184","article-title":"Fresh versus frozen embryo transfers in assisted reproduction.","volume":"3","author":"Wong","year":"2017","journal-title":"Cochrane Database Syst Rev"},{"key":"R4-20250503","doi-asserted-by":"crossref","first-page":"808","DOI":"10.1093\/humupd\/dmu027","article-title":"Fresh versus frozen embryo transfer: backing clinical decisions with scientific and clinical evidence.","volume":"20","author":"Evans","year":"2014","journal-title":"Hum Reprod Update"},{"key":"R5-20250503","doi-asserted-by":"crossref","first-page":"1697","DOI":"10.1093\/humrep\/deac125","article-title":"Should any use of artificial cycle regimen for frozen-thawed embryo transfer in women capable of ovulation be abandoned: yes, but what\u2019s next for FET cycle practice and research?","volume":"37","author":"von Versen-H\u00f6ynck","year":"2022","journal-title":"Hum Reprod"},{"key":"R6-20250503","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.fertnstert.2014.04.018","article-title":"Clinical rationale for cryopreservation of entire embryo cohorts in lieu of fresh transfer.","volume":"102","author":"Shapiro","year":"2014","journal-title":"Fertil Steril"},{"key":"R7-20250503","doi-asserted-by":"crossref","first-page":"1994","DOI":"10.1200\/JCO.2018.78.1914","article-title":"Fertility preservation in patients with cancer: ASCO clinical practice guideline update.","volume":"36","author":"Oktay","year":"2018","journal-title":"J Clin Oncol"},{"key":"R8-20250503","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1016\/j.mayocp.2019.10.009","article-title":"Fertility preservation in women: indications and options for therapy.","volume":"95","author":"Hussein","year":"2020","journal-title":"Mayo Clin Proc"},{"key":"R9-20250503","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1038\/nrendo.2013.205","article-title":"Fertility preservation in women.","volume":"9","author":"Donnez","year":"2013","journal-title":"Nat Rev Endocrinol"},{"key":"R10-20250503","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1186\/1472-6750-11-29","article-title":"Vitrification in open and closed carriers at different cell stages: assessment of embryo survival, development, DNA integrity and stability during vapor phase storage for transport.","volume":"11","author":"AbdelHafez","year":"2011","journal-title":"BMC Biotechnol"},{"key":"R11-20250503","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1055\/a-1326-1830","article-title":"Storage time of cryopreserved embryos and pregnancy outcomes: a dose-response meta-analysis.","volume":"81","author":"Ma","year":"2021","journal-title":"Geburtshilfe Frauenheilkd"},{"key":"R12-20250503","doi-asserted-by":"crossref","first-page":"724853","DOI":"10.3389\/fendo.2021.724853","article-title":"The impact of embryo storage time on pregnancy and perinatal outcomes and the time limit of vitrification: a retrospective cohort study.","volume":"12","author":"Cui","year":"2021","journal-title":"Front Endocrinol (Lausanne)"},{"key":"R13-20250503","doi-asserted-by":"crossref","first-page":"1675","DOI":"10.1093\/humrep\/deaa136","article-title":"The effect of storage time after vitrification on pregnancy and neonatal outcomes among 24 698 patients following the first embryo transfer cycles.","volume":"35","author":"Li","year":"2020","journal-title":"Hum Reprod"},{"key":"R14-20250503","first-page":"925","article-title":"CSRM committee opinions regarding the time limit of embryo cryopreservation.","volume":"27","author":"Quan","year":"2018","journal-title":"J Reprod Med"},{"key":"R15-20250503","doi-asserted-by":"crossref","first-page":"1120.e1","DOI":"10.1016\/j.fertnstert.2010.08.056","article-title":"Live birth from a frozen-thawed pronuclear stage embryo almost 20 years after its cryopreservation.","volume":"95","author":"Dowling-Lacey","year":"2011","journal-title":"Fertil Steril"},{"key":"R16-20250503","doi-asserted-by":"crossref","first-page":"1074","DOI":"10.1016\/S0015-0282(02)03066-2","article-title":"Birth of a healthy baby after transfer of embryos that were cryopreserved for 8.9 years.","volume":"77","author":"Quintans","year":"2002","journal-title":"Fertil Steril"},{"key":"R17-20250503","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1093\/humrep\/deh046","article-title":"Twin delivery following 12 years of human embryo cryopreservation: case report.","volume":"19","author":"Revel","year":"2004","journal-title":"Hum Reprod"},{"key":"R18-20250503","doi-asserted-by":"crossref","first-page":"2771.e1","DOI":"10.1016\/j.fertnstert.2010.04.071","article-title":"Live birth after anonymous donation of twice-cryopreserved embryos that had been stored in liquid nitrogen for a cumulative storage time of approximately 13.5 years.","volume":"94","author":"Reed","year":"2010","journal-title":"Fertil Steril"},{"key":"R19-20250503","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1093\/humrep\/dey350","article-title":"What was the fate of human embryos following long-term cryopreservation (\u226512 years) and frozen embryo transfer?","volume":"34","author":"Yuan","year":"2019","journal-title":"Hum Reprod"},{"key":"R20-20250503","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.fertnstert.2007.06.010","article-title":"Cryopreservation of human embryos by vitrification or slow freezing: a systematic review and meta-analysis.","volume":"90","author":"Loutradi","year":"2008","journal-title":"Fertil Steril"},{"key":"R21-20250503","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1016\/j.fertnstert.2019.12.009","article-title":"Vitrification of the human embryo: a more efficient and safer in vitro fertilization treatment.","volume":"113","author":"Nagy","year":"2020","journal-title":"Fertil Steril"},{"key":"R22-20250503","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1186\/s13148-022-01355-y","article-title":"Advantages of vitrification preservation in assisted reproduction and potential influences on imprinted genes.","volume":"14","author":"Chen","year":"2022","journal-title":"Clin Epigenetics"},{"key":"R23-20250503","doi-asserted-by":"crossref","first-page":"10864","DOI":"10.3390\/ijms221910864","article-title":"Cryopreservation of gametes and embryos and their molecular changes.","volume":"22","author":"Estudillo","year":"2021","journal-title":"Int J Mol Sci"},{"key":"R24-20250503","doi-asserted-by":"crossref","first-page":"181","DOI":"10.3390\/biom9050181","article-title":"The use of antifreeze proteins in the cryopreservation of gametes and embryos.","volume":"9","author":"Robles","year":"2019","journal-title":"Biomolecules"},{"key":"R25-20250503","doi-asserted-by":"crossref","first-page":"337","DOI":"10.3390\/antiox10030337","article-title":"Mitochondrial dysfunction and oxidative stress caused by cryopreservation in reproductive cells.","volume":"10","author":"Gualtieri","year":"2021","journal-title":"Antioxidants (Basel)"},{"key":"R26-20250503","doi-asserted-by":"crossref","first-page":"550","DOI":"10.1089\/ars.2019.7986","article-title":"Autophagy in female fertility: a role in oxidative stress and aging.","volume":"32","author":"Peters","year":"2020","journal-title":"Antioxid Redox Signal"},{"key":"R27-20250503","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.bpobgyn.2020.06.012","article-title":"Assisted conception in women of advanced maternal age.","volume":"70","author":"Seshadri","year":"2021","journal-title":"Best Pract Res Clin Obstet Gynaecol"},{"key":"R28-20250503","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1016\/j.fertnstert.2013.12.032","article-title":"Female age-related fertility decline. Committee Opinion No. 589.","volume":"101","year":"2014","journal-title":"Fertil Steril"},{"key":"R29-20250503","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1016\/j.fertnstert.2017.11.031","article-title":"Impact of transfer time on pregnancy outcomes in frozen-embryo transfer cycles.","volume":"109","author":"Lee","year":"2018","journal-title":"Fertil Steril"},{"key":"R30-20250503","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.fertnstert.2008.09.084","article-title":"Does storage time influence postthaw survival and pregnancy outcome? An analysis of 11,768 cryopreserved human embryos.","volume":"93","author":"Riggs","year":"2010","journal-title":"Fertil Steril"},{"key":"R31-20250503","doi-asserted-by":"crossref","first-page":"2950","DOI":"10.1093\/humrep\/det361","article-title":"The time aspect in storing vitrified blastocysts: its impact on survival rate, implantation potential and babies born.","volume":"28","author":"Wirleitner","year":"2013","journal-title":"Hum Reprod"},{"key":"R32-20250503","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1186\/s13048-022-01035-8","article-title":"Effects of vitrified cryopreservation duration on IVF and neonatal outcomes.","volume":"15","author":"Mao","year":"2022","journal-title":"J Ovarian Res"},{"key":"R33-20250503","doi-asserted-by":"crossref","first-page":"709648","DOI":"10.3389\/fendo.2021.709648","article-title":"Prolonged cryopreservation negatively affects embryo transfer outcomes following the elective freeze-all strategy: a multicenter retrospective study.","volume":"12","author":"Zhang","year":"2021","journal-title":"Front Endocrinol (Lausanne)"},{"key":"R34-20250503","doi-asserted-by":"crossref","first-page":"1832","DOI":"10.1093\/humrep\/deab071","article-title":"Immediate versus delayed frozen embryo transfer in patients following a stimulated IVF cycle: a randomized controlled trial.","volume":"36","author":"Li","year":"2021","journal-title":"Hum Reprod"},{"key":"R35-20250503","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1002\/rmb2.12363","article-title":"Meta-analysis of the embryo freezing transfer interval.","volume":"20","author":"Matorras","year":"2021","journal-title":"Reprod Med Biol"},{"key":"R36-20250503","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1093\/humupd\/dmab002","article-title":"Immediate versus postponed frozen embryo transfer after IVF\/ICSI: a systematic review and meta-analysis.","volume":"27","author":"Bergenheim","year":"2021","journal-title":"Hum Reprod Update"},{"key":"R37-20250503","first-page":"CD011184","article-title":"Fresh versus frozen embryo transfers in assisted reproduction.","volume":"2","author":"Zaat","year":"2021","journal-title":"Cochrane Database Syst Rev"},{"key":"R38-20250503","doi-asserted-by":"crossref","first-page":"1310","DOI":"10.1016\/S0140-6736(18)32843-5","article-title":"Frozen versus fresh single blastocyst transfer in ovulatory women: a multicentre, randomized controlled trial.","volume":"393","author":"Wei","year":"2019","journal-title":"Lancet"},{"key":"R39-20250503","doi-asserted-by":"crossref","first-page":"e1004078","DOI":"10.1371\/journal.pmed.1004078","article-title":"Cancer in children born after frozen-thawed embryo transfer: a cohort study.","volume":"19","author":"Sargisian","year":"2022","journal-title":"PLoS Med"},{"key":"R40-20250503","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1186\/s12884-020-02858-3","article-title":"Pregnancy and perinatal outcomes in pregnancies resulting from time interval between a freeze-all cycle and a subsequent frozen-thawed single blastocyst transfer.","volume":"20","author":"Hu","year":"2020","journal-title":"BMC Pregnancy Childbirth"},{"key":"R41-20250503","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1017\/S2040174421000192","article-title":"Effect of embryo cryopreservation duration on pregnancy-related complications and birthweight after frozen-thawed embryo transfer: a retrospective cohort study.","volume":"13","author":"Xu","year":"2022","journal-title":"J Dev Orig Health Dis"},{"key":"R42-20250503","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1186\/s12958-020-00623-x","article-title":"Does the sex ratio of singleton births after frozen single blastocyst transfer differ in relation to blastocyst development?","volume":"18","author":"Lou","year":"2020","journal-title":"Reprod Biol Endocrinol"},{"key":"R43-20250503","doi-asserted-by":"crossref","first-page":"1671","DOI":"10.1095\/biolreprod.104.027987","article-title":"Bovine blastocyst development in vitro: timing, sex, and viability following vitrification.","volume":"71","author":"Nedambale","year":"2004","journal-title":"Biol Reprod"},{"key":"R44-20250503","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.fertnstert.2016.07.1095","article-title":"Delayed blastulation,multinucleation, and expansion grade are independently associated with live-birth rates in frozen blastocyst transfer cycles.","volume":"106","author":"Desai","year":"2016","journal-title":"Fertil Steril"},{"key":"R45-20250503","doi-asserted-by":"crossref","first-page":"R42","DOI":"10.1530\/RAF-22-0008","article-title":"Long-term preservation of germ cells and gonadal tissues at ambient temperatures.","volume":"3","author":"Comizzoli","year":"2022","journal-title":"Reprod Fertil"}],"container-title":["Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.lww.com\/10.1097\/MD.0000000000037542","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,5,3]],"date-time":"2025-05-03T19:01:54Z","timestamp":1746298914000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.lww.com\/10.1097\/MD.0000000000037542"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,3,29]]},"references-count":45,"journal-issue":{"issue":"13","published-print":{"date-parts":[[2024]]}},"URL":"https:\/\/doi.org\/10.1097\/md.0000000000037542","relation":{"has-preprint":[{"id-type":"doi","id":"10.21203\/rs.3.rs-3386489\/v1","asserted-by":"object"}]},"ISSN":["0025-7974","1536-5964"],"issn-type":[{"value":"0025-7974","type":"print"},{"value":"1536-5964","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,3,29]]}}}