{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T05:08:33Z","timestamp":1780463313830,"version":"3.54.1"},"reference-count":25,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T00:00:00Z","timestamp":1780444800000},"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>Background<\/jats:title>\n                    <jats:p>Evidence regarding maternal body mass index (BMI) and intrauterine insemination (IUI) outcomes remains controversial. This study aimed to evaluate such independent associations, focusing on potential non-linear patterns, clinical thresholds, and population-specific heterogeneities.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Data from 1951 couples (3788 cycles) were retrospectively analyzed. Multivariable generalized linear models (GLM), generalized estimating equations (GEE), and Cox proportional hazards models assessed first-cycle, per-cycle, and cumulative success, respectively; generalized additive model (GAM) and two-piecewise linear regression characterized non-linear patterns and thresholds.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      While maternal BMI showed no significant independent association with clinical pregnancy or live birth in the first cycle (all\n                      <jats:italic>P<\/jats:italic>\n                      &amp;gt; 0.05), per-cycle analysis of 3788 cycles revealed a modest positive correlation (pregnancy: aOR 1.04,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.004; live birth: aOR 1.03,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.030). Notably, cumulative success followed a non-linear pattern (\n                      <jats:italic>\n                        P\n                        <jats:sub>LRT<\/jats:sub>\n                      <\/jats:italic>\n                      \u00a0=\u00a00.027), with live birth probability increasing until a BMI of approximately 21.2 kg\/m\u00b2 (aHR: 1.12,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.007) but plateauing thereafter, potentially linked in part to an exploratory observation of higher spontaneous abortion rates in the obesity group (29.03%,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.087). Subgroup analyses suggested potential heterogeneities in these associations across basal FSH levels and treatment protocols used in the first cycle (\n                      <jats:italic>\n                        P\n                        <jats:sub>interaction<\/jats:sub>\n                      <\/jats:italic>\n                      \u00a0=\u00a00.030 and 0.009, respectively). Specifically, for the FSH &amp;lt; 8mIU\/mL group, a non-linear association was suggested (\n                      <jats:italic>\n                        P\n                        <jats:sub>LRT<\/jats:sub>\n                      <\/jats:italic>\n                      \u00a0=\u00a00.020), with success increasing up to approximately 21.2 kg\/m\u00b2 (aHR: 1.12,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.011) and plateauing thereafter. Similarly, for patients whose first cycle used a gonadotropin protocol, a potential reversal was observed beyond approximately 21.0 kg\/m\u00b2 (\n                      <jats:italic>\n                        P\n                        <jats:sub>LRT<\/jats:sub>\n                      <\/jats:italic>\n                      \u00a0=\u00a00.020), where the trend shifted to a significant decline (aHR: 0.81,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0=\u00a00.023).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Maternal BMI appears to exhibit a non-linear, context-dependent association with cumulative IUI success, underscoring the potential need for individualized preconception management.<\/jats:p>\n                  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China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ai-Ai","family":"Wang","sequence":"additional","affiliation":[{"name":"You Zhaoling National Studio for the Inheritance of Famous Traditional Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine","place":["Guangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qi-Long","family":"Yuan","sequence":"additional","affiliation":[{"name":"Department of Reproductive Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine","place":["Guangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ai-Hua","family":"Wu","sequence":"additional","affiliation":[{"name":"Center for Reproductive Medicine, The 10th Affiliated Hospital of Southern Medical University (Dongguan People\u2019s Hospital)","place":["Dongguan, China"]},{"name":"Guangdong Provincial Key Laboratory of Clinical Research on Traditional Chinese Medicine Syndrome","place":["Guangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shan","family":"Lu","sequence":"additional","affiliation":[{"name":"You Zhaoling National Studio for the Inheritance of Famous Traditional Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine","place":["Guangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wen","family":"Zhou","sequence":"additional","affiliation":[{"name":"Department of Reproductive Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine","place":["Guangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,6,3]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1443","DOI":"10.1001\/jama.2023.6251","article-title":"Infertility affects 1 in 6 people 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