{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T00:10:12Z","timestamp":1773879012427,"version":"3.50.1"},"reference-count":67,"publisher":"Wiley","issue":"16","license":[{"start":{"date-parts":[[2025,7,31]],"date-time":"2025-07-31T00:00:00Z","timestamp":1753920000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[2025,8]]},"abstract":"<jats:sec><jats:title>Abstract<\/jats:title><jats:p>A widely held view is that an increased pulmonary arterial (PA) blood flow at birth is not triggered until the onset of lung aeration, but experimental data indicate that the non\u2010ventilatory events of a reduction in lung liquid volume, complete fetal delivery, and umbilical cord clamping can also increase fetal PA flow. However, the effect of cord clamping strategy on the contribution of these non\u2010ventilatory events to birth\u2010related rises in PA flow is unknown. Accordingly, PA blood flow was measured via transit\u2010time flow probe in anaesthetized, acutely instrumented preterm fetal lambs at baseline, after a \u223c35% reduction in lung liquid volume, following complete fetal delivery, and then after (1) delayed cord clamping (DCC) preceded by ventilation lasting \u223c100\u00a0s (<jats:italic>n<\/jats:italic>\u00a0=\u00a011), or (2) early cord clamping (ECC) followed by either a non\u2010asphyxial (\u223c35\u00a0s, <jats:italic>n<\/jats:italic>\u00a0=\u00a010) or an asphyxial interval (\u223c100\u00a0s, \u00a0&lt;\u00a010\u00a0mmHg, <jats:italic>n<\/jats:italic>\u00a0=\u00a010) before ventilation. PA flow rose stepwise after reduction of lung liquid volume (<jats:italic>P\u00a0&lt;\u00a0<\/jats:italic>0.001) and fetal delivery (<jats:italic>P\u00a0&lt;\u00a0<\/jats:italic>0.001), as well as initial ventilation (<jats:italic>P\u00a0&lt;\u00a0<\/jats:italic>0.001) and subsequent DCC (<jats:italic>P\u00a0=\u00a0<\/jats:italic>0.002). PA flow also rose after ECC (<jats:italic>P\u00a0&lt;\u00a0<\/jats:italic>0.001), with flow maintained in the non\u2010asphyxial group, but markedly reduced to near\u2010baseline fetal levels by pulmonary vasoconstriction in the asphyxial group (<jats:italic>P\u00a0=\u00a0<\/jats:italic>0.009), before rising with ventilation (<jats:italic>P\u00a0&lt;\u00a0<\/jats:italic>0.001). Overall, non\u2010ventilatory events cumulatively accounted for \u223c30% of the fetal baseline\u2010to\u2010peak newborn increment in PA flow. These findings suggest that (1) non\u2010ventilatory events substantially contribute to a perinatal rise in PA blood flow with ECC or DCC, and (2) this contribution is negated if an asphyxial level of arterial oxygenation develops after ECC.\n<jats:boxed-text content-type=\"graphic\" position=\"anchor\"><jats:graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" mimetype=\"image\/png\" position=\"anchor\" specific-use=\"enlarged-web-image\" xlink:href=\"graphic\/tjp70014-gra-0001-m.png\"><jats:alt-text>image<\/jats:alt-text><\/jats:graphic><\/jats:boxed-text><\/jats:p><\/jats:sec><jats:sec><jats:title>Key points<\/jats:title><jats:p><jats:list list-type=\"bullet\">\n<jats:list-item><jats:p>Although a widely held view is that an increased pulmonary blood flow (PBF) at birth is not triggered until onset of lung aeration, reduction of lung liquid volume, complete fetal delivery and umbilical cord clamping also increase fetal PBF.<\/jats:p><\/jats:list-item>\n<jats:list-item><jats:p>The contribution of these non\u2010ventilatory events to birth\u2010related rises in PBF is unknown, particularly with different cord clamping strategies.<\/jats:p><\/jats:list-item>\n<jats:list-item><jats:p>Anaesthetized preterm fetal lambs instrumented with central arterial flow probes underwent birth via delayed cord clamping (DCC) preceded by ventilation, or early cord clamping (ECC) followed by either a non\u2010asphyxial or asphyxial interval before ventilation.<\/jats:p><\/jats:list-item>\n<jats:list-item><jats:p>PBF rose with reduction of lung liquid volume, fetal delivery, ECC and DCC. However, while an increased PBF after ECC was maintained with a non\u2010asphyxial interval, it fell markedly after ECC with an asphyxial interval, before rebounding with ventilation.<\/jats:p><\/jats:list-item>\n<jats:list-item><jats:p>Cumulatively, non\u2010ventilatory events accounted for \u223c 30% of the perinatal increase in PBF occurring with DCC or ECC birth strategies.<\/jats:p><\/jats:list-item>\n<\/jats:list><\/jats:p><\/jats:sec>","DOI":"10.1113\/jp288749","type":"journal-article","created":{"date-parts":[[2025,7,31]],"date-time":"2025-07-31T23:39:29Z","timestamp":1754005169000},"page":"4681-4699","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Non\u2010ventilatory events substantially contribute to rise in pulmonary arterial blood flow with early or delayed cord clamping at birth in preterm lambs"],"prefix":"10.1113","volume":"603","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7363-0172","authenticated-orcid":false,"given":"Joseph J.","family":"Smolich","sequence":"first","affiliation":[{"name":"Heart Research Murdoch Children's Research Institute Parkville Victoria Australia"},{"name":"Department of Paediatrics University of Melbourne  Parkville Victoria Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,7,31]]},"reference":[{"key":"e_1_2_5_2_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpheart.1989.257.2.H626"},{"key":"e_1_2_5_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0002-9378(98)80004-5"},{"key":"e_1_2_5_4_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2012.250084"},{"key":"e_1_2_5_5_1","doi-asserted-by":"publisher","DOI":"10.1172\/JCI119665"},{"key":"e_1_2_5_6_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1983.sp014929"},{"key":"e_1_2_5_7_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1967.sp008290"},{"key":"e_1_2_5_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/ar.24344"},{"key":"e_1_2_5_9_1","first-page":"H1474","article-title":"Effects of birth\u2010related stimuli on L\u2010arginine\u2010dependent pulmonary vasodilation in ovine fetus","volume":"262","author":"Cornfield D. 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