{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T05:06:13Z","timestamp":1791435973934,"version":"4.3.3"},"reference-count":40,"publisher":"Public Library of Science (PLoS)","issue":"2","license":[{"start":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T00:00:00Z","timestamp":1740096000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Chaire de recherche internationale en sant\u00e9 neuromusculosquelettique"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>During pregnancy, increased hormonal levels contribute to ligament laxity of the pelvis and could predispose to lumbopelvic pain. The main objective of this study was to assess changes in pregnancy-related hormones, neuromechanical adaptations and clinical pain status throughout pregnancy. An exploratory objective was to examine the possible association between those variables. Twenty-eight pregnant women participated in the study. At each trimester, they provided a blood sample (to measure relaxin, estrogen and progesterone), completed questionnaires assessing clinical status (functional disability, risk of poor prognosis of prolonged lumbar disability, avoidance behaviors, anxiety and pain catastrophizing), and were asked to perform a flexion-relaxation task (erector spinae electromyography and trunk kinematics). Results showed that throughout pregnancy, nocturnal and diurnal lumbopelvic pain intensity and related-disability, risk of poor lumbopelvic pain prognosis as well as avoidance behaviors increased, while pain catastrophizing decreased. Neuromechanical characteristics of flexion-relaxation task, including low back muscle activity and trunk kinematics, were similar across the three trimesters. Positive correlations were found between disability and estrogen levels (changes between first and second trimester, p = 0.05), and estrogen and diurnal lumbopelvic pain intensity (change between second and third trimester, p = 0.02). A positive correlation was also found between weight and the Pelvic Girdle Questionnaire score (changes between second and third trimester, p = 0.05). Negative correlations were found between weight (change between first and second trimester) and lumbopelvic maximal angle (p = 0.003), FRP onset for pelvic (p = 0.04) and lumbopelvic (p = 0.003) angles as well as FRP cessation for lumbopelvic angle (p = 0.001). These results show that, in pregnant women, pain and disability are associated with hormonal changes rather than trunk neuromechanical characteristics during a flexion-relaxation task. These results suggest that the flexion-relaxation task may not be an appropriate proxy to study vertebral and pelvic muscle control in pregnant women.<\/jats:p>","DOI":"10.1371\/journal.pone.0314158","type":"journal-article","created":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T18:41:52Z","timestamp":1740163312000},"page":"e0314158","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":12,"title":["Changes in pregnancy-related hormones, neuromechanical adaptations and clinical pain status throughout pregnancy: A prospective cohort study"],"prefix":"10.1371","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9627-9290","authenticated-orcid":true,"given":"Catherine","family":"Daneau","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fran\u00e7ois","family":"Nougarou","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacques","family":"Abboud","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephanie-May","family":"Ruchat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Descarreaux","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,2,21]]},"reference":[{"issue":"6","key":"pone.0314158.ref001","doi-asserted-by":"crossref","first-page":"794","DOI":"10.1007\/s00586-008-0602-4","article-title":"European guidelines for the diagnosis and treatment of pelvic girdle pain","volume":"17","author":"A Vleeming","year":"2008","journal-title":"Eur Spine J"},{"issue":"8","key":"pone.0314158.ref002","doi-asserted-by":"crossref","first-page":"1038","DOI":"10.1016\/j.jogc.2017.10.032","article-title":"Prevalence of low back pain, pelvic girdle pain, and combination pain in a pregnant Ontario population","volume":"40","author":"CA Weis","year":"2018","journal-title":"J Obstet Gynaecol Can"},{"issue":"4","key":"pone.0314158.ref003","doi-asserted-by":"crossref","first-page":"304","DOI":"10.2340\/16501977-0170","article-title":"Association between muscle function and low back pain in relation to pregnancy","volume":"40","author":"A Gutke","year":"2008","journal-title":"J Rehabil Med"},{"issue":"4","key":"pone.0314158.ref004","doi-asserted-by":"crossref","first-page":"510","DOI":"10.1089\/jwh.2017.6342","article-title":"The severity and impact of pelvic girdle pain and low-back pain in pregnancy: a multinational study","volume":"27","author":"A Gutke","year":"2018","journal-title":"J Women's Health (2002)"},{"issue":"1","key":"pone.0314158.ref005","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/j.knee.2008.09.005","article-title":"The effect of relaxin on the female anterior cruciate ligament: analysis of mechanical properties in an animal model","volume":"16","author":"JL Dragoo","year":"2009","journal-title":"Knee"},{"key":"pone.0314158.ref006","volume-title":"Maternal, Fetal, & Neonatal physiology: a clinical perspcetive","author":"ST Blackburn","year":"2018"},{"key":"pone.0314158.ref007","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1007\/978-3-319-14319-4_2","article-title":"Hormonal influence on the neuromusculoskeletal system in pregnancy.","volume-title":"Musculoskeletal health in pregnancy and postpartum: an evidence-based guide for clinicians","author":"ME Reese","year":"2015"},{"issue":"4","key":"pone.0314158.ref008","doi-asserted-by":"crossref","first-page":"e220","DOI":"10.1111\/sms.12149","article-title":"The effect of relaxin on the musculoskeletal system","volume":"24","author":"F Dehghan","year":"2014","journal-title":"Scand J Med Sci Sports"},{"issue":"7172","key":"pone.0314158.ref009","doi-asserted-by":"crossref","first-page":"1075","DOI":"10.1038\/nature06342","article-title":"Fetal load and the evolution of lumbar lordosis in bipedal hominins","volume":"450","author":"KK Whitcome","year":"2007","journal-title":"Nature"},{"issue":"1","key":"pone.0314158.ref010","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1054\/math.1998.0311","article-title":"Insufficient lumbopelvic stability: a clinical, anatomical and biomechanical approach to \u2018a-specific\u2019low back pain","volume":"3","author":"A Pool-Goudzwaard","year":"1998","journal-title":"Manual therapy"},{"issue":"5","key":"pone.0314158.ref011","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1080\/00016340600578415","article-title":"Risk factors in developing pregnancy\u2010related pelvic girdle pain","volume":"85","author":"HB Albert","year":"2006","journal-title":"Acta Obstet Gynecol Scand"},{"key":"pone.0314158.ref012","doi-asserted-by":"crossref","first-page":"773988","DOI":"10.3389\/fpain.2021.773988","article-title":"Mechanisms underlying lumbopelvic pain during pregnancy: a proposed model","volume":"2","author":"C Daneau","year":"2021","journal-title":"Front Pain Res"},{"key":"pone.0314158.ref013","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1097\/00002517-199212000-00001","article-title":"Function, dysfunction, adaptation, and enhancement","volume":"5","year":"1992","journal-title":"J Spinal Disord"},{"issue":"1","key":"pone.0314158.ref014","first-page":"71","article-title":"The sensorimotor system, part I: the physiologic basis of functional joint stability","volume":"37","author":"BL Riemann","year":"2002","journal-title":"J Athl Train"},{"issue":"3","key":"pone.0314158.ref015","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1097\/OGX.0b013e3181950f1b","article-title":"Mobility of the pelvic joints in pregnancy-related lumbopelvic pain: a systematic review","volume":"64","author":"JM Mens","year":"2009","journal-title":"Obst Gynecol Surv"},{"issue":"8","key":"pone.0314158.ref016","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1016\/j.jmpt.2005.08.005","article-title":"The biomechanical and clinical significance of the lumbar erector spinae flexion-relaxation phenomenon: a review of literature","volume":"28","author":"CJ Colloca","year":"2005","journal-title":"J Manipulative Physiol Ther"},{"issue":"10","key":"pone.0314158.ref017","doi-asserted-by":"crossref","first-page":"1210","DOI":"10.1016\/S0003-9993(98)90264-7","article-title":"Functional changes in back muscle activity correlate with pain intensity and prediction of low back pain during pregnancy","volume":"79","author":"T Sihvonen","year":"1998","journal-title":"Arch Phys Med Rehabil"},{"issue":"3","key":"pone.0314158.ref018","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/S1050-6411(02)00028-7","article-title":"Sensorimotor control of the spine","volume":"12","author":"S Holm","year":"2002","journal-title":"J Electromyogr kinesiol"},{"issue":"4","key":"pone.0314158.ref019","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1016\/S0021-9290(00)00213-X","article-title":"Analyses of myo-electrical silence of erectors spinae","volume":"34","author":"A Gupta","year":"2001","journal-title":"J Biomech"},{"issue":"5","key":"pone.0314158.ref020","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1016\/S0268-0033(02)00023-2","article-title":"Examination of the flexion relaxation phenomenon in erector spinae muscles during short duration slumped sitting","volume":"17","author":"JP Callaghan","year":"2002","journal-title":"Clin Biomech (Bristol, Avon)"},{"issue":"18","key":"pone.0314158.ref021","doi-asserted-by":"crossref","first-page":"E421","DOI":"10.1097\/00007632-200109150-00019","article-title":"Response of the flexion\u2013relaxation phenomenon relative to the lumbar motion to load and speed","volume":"26","author":"M Sarti","year":"2001","journal-title":"Spine"},{"issue":"8","key":"pone.0314158.ref022","doi-asserted-by":"crossref","first-page":"769","DOI":"10.1016\/j.clinbiomech.2004.05.007","article-title":"Flexion-relaxation response to cyclic lumbar flexion","volume":"19","author":"MW Olson","year":"2004","journal-title":"Clin Biomech (Bristol, Avon)"},{"issue":"1","key":"pone.0314158.ref023","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1471-2474-11-112","article-title":"Changes in the flexion-relaxation response induced by hip extensor and erector spinae muscle fatigue","volume":"11","author":"M Descarreaux","year":"2010","journal-title":"BMC Musculoskelet Disord"},{"issue":"1","key":"pone.0314158.ref024","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1471-2474-9-10","article-title":"Changes in the flexion relaxation response induced by lumbar muscle fatigue","volume":"9","author":"M Descarreaux","year":"2008","journal-title":"BMC Musculoskelet Disord"},{"issue":"5","key":"pone.0314158.ref025","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1139\/y91-102","article-title":"The pain-adaptation model: a discussion of the relationship between chronic musculoskeletal pain and motor activity","volume":"69","author":"JP Lund","year":"1991","journal-title":"Can J Physiol Pharmacol"},{"issue":"5","key":"pone.0314158.ref026","doi-asserted-by":"crossref","first-page":"486","DOI":"10.1016\/S0003-9993(97)90161-1","article-title":"Flexion relaxation of the hamstring muscles during lumbar-pelvic rhythm","volume":"78","author":"T Sihvonen","year":"1997","journal-title":"Arch Phys Med Rehabil"},{"key":"pone.0314158.ref027","first-page":"136","article-title":"The flexion relaxation phenomenon in nonspecific chronic low back pain: prevalence, reproducibility and flexion\u2013extension ratios. A systematic review and meta-analysis","author":"A Gouteron","year":"2021","journal-title":"Eur Spine J"},{"issue":"3","key":"pone.0314158.ref028","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/S0268-0033(97)00065-X","article-title":"Surface electromyography in the identification of chronic low back pain patients: the development of the flexion relaxation ratio","volume":"12","author":"PJ Watson","year":"1997","journal-title":"Clin Biomech"},{"issue":"2","key":"pone.0314158.ref029","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1016\/j.spinee.2018.08.009","article-title":"Effects of pregnancy on lumbar motion patterns and muscle responses","volume":"19","author":"G Bivi\u00e1-Roig","year":"2019","journal-title":"Spine J"},{"issue":"1","key":"pone.0314158.ref030","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1007\/s00586-002-0464-0","article-title":"The clinical importance of changes in outcome scores after treatment for chronic low back pain","volume":"12","author":"Swedish Lumbar Spine Study Group","year":"2003","journal-title":"Eur Spine J"},{"issue":"12","key":"pone.0314158.ref031","doi-asserted-by":"crossref","first-page":"2545","DOI":"10.1016\/j.pain.2014.09.014","article-title":"Cut-off points for mild, moderate, and severe pain on the visual analogue scale for pain in patients with chronic musculoskeletal pain","volume":"155","author":"AM Boonstra","year":"2014","journal-title":"Pain"},{"key":"pone.0314158.ref032","doi-asserted-by":"crossref","first-page":"102438","DOI":"10.1016\/j.jelekin.2020.102438","article-title":"Consensus for experimental design in electromyography (CEDE) project: amplitude normalization matrix","volume":"53","author":"M Besomi","year":"2020","journal-title":"J Electromyogr Kinesiol"},{"issue":"11","key":"pone.0314158.ref033","doi-asserted-by":"crossref","first-page":"e022508","DOI":"10.1136\/bmjopen-2018-022508","article-title":"Lumbopelvic pain, anxiety, physical activity and mode of conception: a prospective cohort study of pregnant women","volume":"8","author":"E Lardon","year":"2018","journal-title":"BMJ Open"},{"issue":"1","key":"pone.0314158.ref034","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.rehab.2008.10.002","article-title":"Kinematic and electromyographic parameters of the cervical flexion\u2013relaxation phenomenon: the effect of trunk positioning","volume":"52","author":"J-P Pialasse","year":"2009","journal-title":"Ann Phys Rehabil Med"},{"key":"pone.0314158.ref035","doi-asserted-by":"crossref","first-page":"105716","DOI":"10.1016\/j.clinbiomech.2022.105716","article-title":"Motor control of the spine in pregnancy-related lumbopelvic pain: a systematic review","volume":"98","author":"A Desgagn\u00e9s","year":"2022","journal-title":"Clin Biomech"},{"issue":"7","key":"pone.0314158.ref036","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1016\/j.jmpt.2021.10.001","article-title":"Association Between Pregnancy-Related Hormones and Lumbopelvic Pain Characteristics in Pregnant Women: A Scoping Review","volume":"44","author":"C Daneau","year":"2021","journal-title":"J Manipulative Physiol Ther"},{"issue":"1 Pt 1","key":"pone.0314158.ref037","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/S0002-9378(99)70162-6","article-title":"Reproductive hormones and aminoterminal propeptide of type III procollagen in serum as early markers of pelvic pain during late pregnancy","volume":"180","author":"P Kristiansson","year":"1999","journal-title":"Am J Obstet Gynecol"},{"issue":"7","key":"pone.0314158.ref038","doi-asserted-by":"crossref","first-page":"494","DOI":"10.1016\/j.jmpt.2014.07.003","article-title":"Quantification of the lumbar flexion-relaxation phenomenon: comparing outcomes of lumbar erector spinae and superficial lumbar multifidus in standing full trunk flexion and slumped sitting postures","volume":"37","author":"A Schinkel-Ivy","year":"2014","journal-title":"J Manipulative Physiol Ther"},{"key":"pone.0314158.ref039","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1007\/s00586-003-0615-y","article-title":"Pregnancy-related pelvic girdle pain (PPP), I: terminology, clinical presentation, and prevalence","volume":"13","author":"W-H Wu","year":"2004","journal-title":"Eur Spine J"},{"issue":"1","key":"pone.0314158.ref040","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.ejogrb.2004.11.021","article-title":"A historical perspective on pregnancy-related low back and\/or pelvic girdle pain.","volume":"120","author":"JM Bastiaanssen","year":"2005","journal-title":"Eur J Obst Gynecol Reprod Biol"}],"container-title":["PLOS ONE"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0314158","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T18:42:08Z","timestamp":1740163328000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0314158"}},"subtitle":[],"editor":[{"given":"Charlie M.","family":"Waugh","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2025,2,21]]},"references-count":40,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2025,2,21]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0314158","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,2,21]]}}}