{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T14:14:06Z","timestamp":1788444846748,"version":"build-2803163510"},"reference-count":22,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T00:00:00Z","timestamp":1780358400000},"content-version":"unspecified","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"The 111 Project","award":["Yuwaizhuan (2016)32"],"award-info":[{"award-number":["Yuwaizhuan (2016)32"]}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,5,15]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>The progressive adaptation of the maternal cardiovascular system throughout pregnancy is essential to maintaining adequate uteroplacental circulation and meeting maternal physiological demands. In recent years, maternal haemodynamic parameters have gained attention as useful indicators for screening and managing pregnancy, particularly for identifying women at high risk for complications and predicting adverse pregnancy outcomes. The aim of this study is to assess the trajectory of haemodynamic parameters during labour, establish reference ranges for different stages of labour and explore the association between haemodynamics and adverse pregnancy outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods and analysis<\/jats:title>\n                    <jats:p>This is an ambispective observational cohort study conducted in a tertiary hospital in Chongqing, China. A total of 2800 pregnant women will be enrolled. After hospital admission and providing written informed consent, participants will complete a demographic questionnaire. Data collection will include maternal baseline characteristics, haemodynamic parameters at multiple stages of labour and maternal and newborn outcomes. These data will allow comprehensive analysis of haemodynamic changes during labour in women undergoing vaginal delivery.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Ethics and dissemination<\/jats:title>\n                    <jats:p>This study has been approved by the Research Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (ethics approval number: 2024\u2013406-01). Participation is voluntary and initiated only after obtaining written informed consent. The findings will be disseminated through presentations at national and international conferences and through publications in peer-reviewed scientific journals.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial registration number<\/jats:title>\n                    <jats:p>ChiCTR2500097643.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2025-106885","type":"journal-article","created":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T17:50:32Z","timestamp":1780422632000},"page":"e106885","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Investigating haemodynamic changes during vaginal delivery in low-risk pregnant women and the association between haemodynamic and adverse pregnancy outcomes: an ambispective cohort study protocol"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-1800-5584","authenticated-orcid":false,"given":"Cheng","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dawei","family":"Guo","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ting","family":"Zhou","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Public Health, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zaimei","family":"Tang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3501-8385","authenticated-orcid":false,"given":"Hua","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Longqiong","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinyang","family":"Yu","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,6,2]]},"reference":[{"key":"2026090306260809000_16.6.e106885.1","doi-asserted-by":"publisher","DOI":"10.1097\/HJH.0b013e3283588189"},{"key":"2026090306260809000_16.6.e106885.2","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1002\/uog.19067","article-title":"Maternal hemodynamics, fetal biometry and Doppler indices in pregnancies followed up for suspected fetal growth restriction","volume":"52","author":"Roberts","year":"2018","journal-title":"Ultrasound Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.3","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9378(82)90616-0"},{"key":"2026090306260809000_16.6.e106885.4","doi-asserted-by":"publisher","DOI":"10.1097\/ACO.0b013e32834588c5"},{"key":"2026090306260809000_16.6.e106885.5","doi-asserted-by":"publisher","DOI":"10.1007\/s00125-019-4840-2"},{"key":"2026090306260809000_16.6.e106885.6","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1002\/uog.21941","article-title":"Impact of gestational diabetes mellitus on maternal cardiac adaptation to pregnancy","volume":"56","author":"Buddeberg","year":"2020","journal-title":"Ultrasound Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.7","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1111\/1471-0528.17667","article-title":"Reference ranges for third-trimester maternal cardiovascular function parameters measured in normotensive pregnant women using a non-invasive cardiac output monitor: A study based on data from the prospective PEACH cohort study","volume":"131","author":"Lihme","year":"2024","journal-title":"BJOG"},{"key":"2026090306260809000_16.6.e106885.8","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1002\/uog.17504","article-title":"Maternal hemodynamics in normal pregnancy: reference ranges and role of maternal characteristics","volume":"51","author":"Vinayagam","year":"2018","journal-title":"Ultrasound Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.9","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.295.6607.1169"},{"key":"2026090306260809000_16.6.e106885.10","doi-asserted-by":"crossref","first-page":"1104","DOI":"10.1016\/S0002-9378(66)80011-X","article-title":"Cardiovascular responses to labor and delivery","volume":"95","author":"Winner","year":"1966","journal-title":"Am J Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.11","first-page":"343","article-title":"Changes of cardiac output during labour in healthy term pregnant women of reproductive age","volume":"25","author":"Wei","year":"2022","journal-title":"Chin J Perinat Med"},{"key":"2026090306260809000_16.6.e106885.12","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.ijoa.2017.03.003","article-title":"Haemodynamic changes during labour: continuous minimally invasive monitoring in 20 healthy parturients","volume":"31","author":"Kuhn","year":"2017","journal-title":"Int J Obstet Anesth"},{"key":"2026090306260809000_16.6.e106885.13","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1080\/01443619750113249","article-title":"Cardiac output monitoring during vaginal delivery","volume":"17","author":"Filippatos","year":"1997","journal-title":"J Obstet Gynaecol"},{"key":"2026090306260809000_16.6.e106885.14","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1111\/hdi.12589","article-title":"Comparison of stroke volume measurements during hemodialysis using bioimpedance cardiography and echocardiography","volume":"22","author":"Germain","year":"2018","journal-title":"Hemodial Int"},{"key":"2026090306260809000_16.6.e106885.15","doi-asserted-by":"crossref","first-page":"101457","DOI":"10.1016\/j.cpcardiol.2022.101457","article-title":"Correlation of Impedance Cardiography-Derived and Cardiac Magnetic Resonance-Derived Stroke Volumes","volume":"48","author":"Hassan-Tash","year":"2023","journal-title":"Curr Probl Cardiol"},{"key":"2026090306260809000_16.6.e106885.16","first-page":"644","article-title":"Study on the Appropriateness of Parameters in Sample Size Estimation Method of Reference Range","volume":"36","author":"Xia","year":"2019","journal-title":"Chin J Health Stat"},{"key":"2026090306260809000_16.6.e106885.17","doi-asserted-by":"crossref","DOI":"10.1542\/peds.2017-2467","article-title":"Monitoring the Postnatal Growth of Preterm Infants: A Paradigm Change","volume":"141","author":"Villar","year":"2018","journal-title":"Pediatrics"},{"key":"2026090306260809000_16.6.e106885.18","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.ajog.2020.08.110","article-title":"International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project","volume":"224","author":"Rizzo","year":"2021","journal-title":"Am J Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.19","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1002\/uog.17447","article-title":"Maternal hemodynamics early in labor: a possible link with obstetric risk?","volume":"51","author":"Valensise","year":"2018","journal-title":"Ultrasound Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.20","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1002\/uog.21918","article-title":"Maternal cardiovascular function and risk of intrapartum fetal compromise in women undergoing induction of labor: pilot study","volume":"56","author":"Kalafat","year":"2020","journal-title":"Ultrasound Obstet Gynecol"},{"key":"2026090306260809000_16.6.e106885.21","doi-asserted-by":"crossref","DOI":"10.1186\/s12884-018-1861-7","article-title":"Maternal cardiovascular hemodynamics in normotensive versus preeclamptic pregnancies: a prospective longitudinal study using a noninvasive cardiac system (NICaS)","volume":"18","author":"Lavie","year":"2018","journal-title":"BMC Pregnancy Childbirth"},{"key":"2026090306260809000_16.6.e106885.22","doi-asserted-by":"crossref","first-page":"S167","DOI":"10.1016\/j.ajog.2014.10.357","article-title":"311: Cardiac hemodynamics in labor and postpartum \u2013 A new look into physiology","volume":"212","author":"Ashwal","year":"2015","journal-title":"Am J Obstet Gynecol"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2025-106885","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T13:27:10Z","timestamp":1788442030000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2025-106885"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6]]},"references-count":22,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6,2]]},"published-print":{"date-parts":[[2026,6]]}},"alternative-id":["10.1136\/bmjopen-2025-106885"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2025-106885","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6]]}}}