{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,27]],"date-time":"2025-11-27T11:10:48Z","timestamp":1764241848267,"version":"3.46.0"},"reference-count":58,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T00:00:00Z","timestamp":1762214400000},"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. Med."],"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To investigate whether umbilical cord traction triggers a unique umbilico-neuro-cardio reflex via sympathetic autonomic nervous system (ANS) activation, potentially explaining fetal heart rate (FHR) increases such as the double mountain peak sign and unexplained tachycardia outside labor.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Experimental physiological study using the EXTrauterine Environment for Neonatal Development (EXTEND) system.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Controlled laboratory environment at The Children\u2019s Hospital of Philadelphia with fetal lambs supported by the EXTEND system.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Population or sample<\/jats:title>\n                    <jats:p>Twenty-nine experiments were performed on three fetal lambs: 5 ANS-immature (&amp;lt;110\u202fdays gestational age) and 24 ANS-mature (&amp;gt;110\u202fdays GA), including subgroups for pharmacological intervention.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Umbilical cord traction was performed in 20 experiments (5 ANS-immature, 15 ANS-mature). To investigate autonomic modulation, nine ANS-mature experiments included administration of either periumbilical capsaicin or intravenous propranolol. FHR changes were measured, and norepinephrine levels were sampled before and after interventions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Main outcome measures<\/jats:title>\n                    <jats:p>Change in FHR (bpm) and circulating norepinephrine concentrations in response to umbilical cord traction and pharmacologic modulation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Cord traction significantly increased FHR in ANS-mature lambs (mean +42\u202fbpm,\n                      <jats:italic>p<\/jats:italic>\n                      \u202f&amp;lt;\u202f0.001), but not in ANS-immature lambs (mean +1\u202fbpm,\n                      <jats:italic>p<\/jats:italic>\n                      \u202f=\u202f0.770). Capsaicin also elevated FHR and norepinephrine, while propranolol inhibited both responses.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Umbilical cord traction appears to activate an umbilico-neuro-cardiac reflex through sympathetic ANS pathways in ANS-mature fetuses. This mechanism may underlie clinical CTG features such as the double mountain peak sign and fetal tachycardia outside of labor.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmed.2025.1667607","type":"journal-article","created":{"date-parts":[[2025,11,27]],"date-time":"2025-11-27T11:07:29Z","timestamp":1764241649000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Fetal heart and surroundings: umbilical cord traction triggers sympathetic heart rate surge in fetal lambs in the artificial womb"],"prefix":"10.3389","volume":"12","author":[{"given":"Maria Antonietta","family":"Castaldi","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Salvatore Giovanni","family":"Castaldi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria 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