{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T11:27:15Z","timestamp":1788175635889,"version":"build-2803163510"},"reference-count":35,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,10,28]],"date-time":"2022-10-28T00:00:00Z","timestamp":1666915200000},"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>To explore the association between endometrial thickness (EMT) and adverse neonatal outcomes in frozen <jats:italic>in vitro<\/jats:italic> fertilization\/intracytoplasmic sperm injection-embryo transfer (IVF\/ICSI-ET) cycles.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>This retrospective study involved a total of 8,235 women under the age of 35 years who underwent IVF\/ICSI cycles and received frozen embryo transfer (FET) at a tertiary-care academic medical from January 2015 to December 2019, resulting in a live singleton newborn. Patients were categorized into three groups depending on EMT: \u22647.5 mm, 7.5-12 mm and &amp;gt;12 mm. The primary outcome was low birthweight (LBW). The secondary outcomes were preterm birth (PTB), small-for-gestational age (SGA), large-for-gestational age (LGA) and high birthweight (HBW).<\/jats:p><\/jats:sec><jats:sec><jats:title>Result(s)<\/jats:title><jats:p>Compared with EMT &amp;gt;7.5\u201312 mm group, the risk of being born LBW was statistically significantly increased in the EMT \u22647.5 mm group (adjusted odds ratio [aOR] 2.179; 95% confidence interval [CI], 1.305\u20133.640; P=.003), while dramatically decreased in the EMT &amp;gt;12 mm group (aOR 0.584; 95% CI, 0.403-0.844; P=.004). Moreover, newborn gender and pregnancy complications were all independent predictors for LBW. Furthermore, a significant decrease in birthweight was found in the EMT \u22647.5 mm group as compared with EMT &amp;gt;7.5\u201312 mm group and EMT &amp;gt;12 mm group (3,239 \u00b1 612 vs. 3,357 \u00b1 512 and 3,374 \u00b1 479 g, respectively), and similar result was found in term of gestational age (38.41 \u00b1 2.19 vs. 39.01 \u00b1 1.68 and 39.09 \u00b1 1.5 weeks, respectively).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion(s)<\/jats:title><jats:p>After frozen IVF\/ICSI-ET, EMT \u22647.5 mm is independently associated with increased risk of LBW among women with singleton newborns. Therefore, we suggest that women with EMT \u22647.5 mm after achieving pregnancy by IVF\/ICSI-ET treatment should warrant more attention to reduce the risk of delivering a LBW newborn.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fendo.2022.929617","type":"journal-article","created":{"date-parts":[[2022,10,28]],"date-time":"2022-10-28T06:18:01Z","timestamp":1666937881000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":10,"title":["Endometrial thickness is associated with low birthweight in frozen embryo transfer cycles: A retrospective cohort study of 8,235 singleton 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