{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T21:25:47Z","timestamp":1783632347630,"version":"3.55.0"},"reference-count":59,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,5,31]],"date-time":"2024-05-31T00:00:00Z","timestamp":1717113600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Leibniz Cooperative Excellence","award":["K438\/2022"],"award-info":[{"award-number":["K438\/2022"]}]},{"name":"Leibniz Cooperative Excellence","award":["310030_212984\/1"],"award-info":[{"award-number":["310030_212984\/1"]}]},{"name":"Leibniz Cooperative Excellence","award":["31003A-156299\/1"],"award-info":[{"award-number":["31003A-156299\/1"]}]},{"name":"Swiss National Science Foundation","award":["K438\/2022"],"award-info":[{"award-number":["K438\/2022"]}]},{"name":"Swiss National Science Foundation","award":["310030_212984\/1"],"award-info":[{"award-number":["310030_212984\/1"]}]},{"name":"Swiss National Science Foundation","award":["31003A-156299\/1"],"award-info":[{"award-number":["31003A-156299\/1"]}]},{"name":"CNRS\/INEE Grant INR Bipedal equilibrium","award":["K438\/2022"],"award-info":[{"award-number":["K438\/2022"]}]},{"name":"CNRS\/INEE Grant INR Bipedal equilibrium","award":["310030_212984\/1"],"award-info":[{"award-number":["310030_212984\/1"]}]},{"name":"CNRS\/INEE Grant INR Bipedal equilibrium","award":["31003A-156299\/1"],"award-info":[{"award-number":["31003A-156299\/1"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>The origin of difficult birth is still a matter of debate in obstetrics. Recent studies hypothesized that early hominins already experienced obstructed labor even with reduced neonatal head sizes. The aim of this work is to test this hypothesis using an extant obstetrical sample with known delivery outcomes. Three delivery outcomes (i.e., instrument-assisted, Caesarean section, and vaginal birth) were evaluated using a discriminant analysis based on 131 mother\u2013baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine \u201cdyads\u201d generated from the combination of six pelvic reconstructions (three for Australopithecus afarensis, two for A. africanus, and one for A. sediba) and three fetal head size estimations. The obstetrical analysis revealed that dystocic births can be predicted by pelvic features such as an anteroposteriorly flattened pelvic inlet. Australopithecines shared these pelvic morphologies with humans and had eutocic birth only for infants of 110 g brain size or smaller, equaling a human-like neonatal\/adult brain size ratio of 25\u201328%. Although birth mechanism cannot be deduced, the newborn\/adult brain size ratio was likely more human-like than previously thought, suggesting that australopithecines were secondarily altricial to circumvent instances of obstructed labor and subsequently require a prolonged postnatal brain growth period, implying some aspects of life history pattern similar to modern humans.<\/jats:p>","DOI":"10.3390\/biology13060398","type":"journal-article","created":{"date-parts":[[2024,5,31]],"date-time":"2024-05-31T03:46:49Z","timestamp":1717127209000},"page":"398","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Obstetrical Constraints and the Origin of Extended Postnatal Brain Maturation in Hominin Evolution"],"prefix":"10.3390","volume":"13","author":[{"given":"Pierre","family":"Fr\u00e9mondi\u00e8re","sequence":"first","affiliation":[{"name":"Faculty of Medical and Paramedical Sciences, School of Midwifery, Aix Marseille University, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France"},{"name":"UMR 7268 ADES, Aix Marseille University, EFS, CNRS, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9100-4183","authenticated-orcid":false,"given":"Martin","family":"Haeusler","sequence":"additional","affiliation":[{"name":"Institute of Evolutionary Medicine, University of Z\u00fcrich, Winterthurerstrasse 190, 8057 Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lionel","family":"Thollon","sequence":"additional","affiliation":[{"name":"LBA, Aix Marseille University, Gustave Eiffel University, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicole M.","family":"Webb","sequence":"additional","affiliation":[{"name":"Institute of Evolutionary Medicine, University of Z\u00fcrich, Winterthurerstrasse 190, 8057 Z\u00fcrich, Switzerland"},{"name":"Department of Palaeoanthropology, Senckenberg Gesellschaft f\u00fcr Naturforschung, Senckenberganlage 25, 60325 Frankfurt am Main, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7479-2360","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Marchal","sequence":"additional","affiliation":[{"name":"UMR 7268 ADES, Aix Marseille University, EFS, CNRS, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,5,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1146\/annurev.an.24.100195.001353","article-title":"Toward a life history of the Hominidae","volume":"24","author":"Smith","year":"1995","journal-title":"Annu. Rev. Anthropol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1002\/(SICI)1098-2345(1996)40:2<99::AID-AJP1>3.0.CO;2-V","article-title":"Perinatal life history traits in New World monkeys","volume":"40","author":"Hartwig","year":"1996","journal-title":"Am. J. Primatol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1002\/evan.20289","article-title":"Primate Milk: Proximate mechanisms and ultimate perspectives","volume":"20","author":"Hinde","year":"2011","journal-title":"Evol. Anthropol."},{"key":"ref_4","first-page":"511","article-title":"Die Tragzeiten der Primaten und die Dauer der Schwangerschaft beim Menschen: Ein Problem der vergleichenden Biologie","volume":"48","author":"Portmann","year":"1941","journal-title":"Rev. Suisse Zool."},{"key":"ref_5","unstructured":"Martin, R.D. (1982, January 27). Human brain evolution in an ecological context. Proceedings of the 52nd James Arthur Lecture on the Evolution of the Human Brain; American Museum of Natural History, New York, NY, USA."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1146\/annurev-anthro-111819-105454","article-title":"The evolution of human infancy: Why it helps to be helpless","volume":"50","author":"Rosenberg","year":"2021","journal-title":"Annu. Rev. Anthropol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1038\/nature02852","article-title":"Early brain growth in Homo erectus and implications for cognitive ability","volume":"431","author":"Coqueugniot","year":"2004","journal-title":"Nature"},{"key":"ref_8","unstructured":"Hrdy, S.B. (2006). Attachment and Bonding: A New Synthesis, The MIT Press."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"262","DOI":"10.1016\/j.jhevol.2009.11.006","article-title":"A new reconstruction of Sts 14 pelvis (Australopithecus africanus) from computed tomography and three-dimensional modeling techniques","volume":"58","author":"Berge","year":"2010","journal-title":"J. Hum. Evol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/S0047-2484(86)80052-5","article-title":"The obstetric pelvis of AL 288-1 (Lucy)","volume":"15","author":"Tague","year":"1986","journal-title":"J. Hum. Evol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Fr\u00e9mondi\u00e8re, P., Thollon, L., Marchal, F., Fornai, C., Webb, N.M., and Haeusler, M. (2022). Dynamic finite-element simulations reveal early origin of complex human birth pattern. Commun. Biol., 5.","DOI":"10.1038\/s42003-022-03321-z"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"326.e1","DOI":"10.1016\/j.ajog.2010.06.058","article-title":"Contemporary cesarean delivery practice in the United States","volume":"203","author":"Zhang","year":"2010","journal-title":"Am. J. Obstet. Gynecol."},{"key":"ref_13","unstructured":"Dolea, C., and AbouZahr, C. (2003). Global Burden of Disease 2000, World Health Organ."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"460.e1","DOI":"10.1016\/j.ajog.2013.02.050","article-title":"Radiographic measures of the mid pelvis to predict cesarean delivery","volume":"208","author":"Harper","year":"2013","journal-title":"Am. J. Obstet. Gynecol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e107","DOI":"10.1016\/j.ejrad.2009.04.042","article-title":"Pelvimetry revisited: Analyzing cephalopelvic disproportion","volume":"74","author":"Lenhard","year":"2010","journal-title":"Eur. J. Radiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"810","DOI":"10.1016\/0002-9378(92)91338-B","article-title":"Efficacy of the fetal-pelvic index in nulliparous women at risk for fetal-pelvic disproportion","volume":"166","author":"Morgan","year":"1992","journal-title":"Am. J. Obstet. Gynecol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1111\/aogs.12608","article-title":"Fetal pelvic index to predict cephalopelvic disproportion\u2014A retrospective clinical cohort study","volume":"94","author":"Korhonen","year":"2015","journal-title":"Acta Obstet. Gynecol. Scand."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1002\/ajpa.1330370605","article-title":"Morphological adaptation to climate in modern and fossil hominids","volume":"37","author":"Ruff","year":"1994","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1016\/j.jhevol.2014.02.021","article-title":"The interaction of neutral evolutionary processes with climatically-driven adaptive changes in the 3D shape of the human os coxae","volume":"73","author":"Betti","year":"2014","journal-title":"J. Hum. Evol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"20140067","DOI":"10.1098\/rstb.2014.0067","article-title":"Between Scylla and Charybdis: Renegotiating resolution of the \u2018obstetric dilemma\u2019 in response to ecological change","volume":"370","author":"Wells","year":"2015","journal-title":"Phil. Trans. R. Soc. B"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"5655","DOI":"10.1073\/pnas.1420325112","article-title":"Covariation between human pelvis shape, stature, and head size alleviates the obstetric dilemma","volume":"112","author":"Fischer","year":"2015","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1002\/ajpa.24103","article-title":"Assessing thoraco-pelvic covariation in Homo sapiens and Pan troglodytes: A 3D geometric morphometric approach","volume":"173","author":"Martelli","year":"2020","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"890","DOI":"10.1002\/ar.23573","article-title":"Neonatal shoulder width suggests a semirotational, oblique birth mechanism in Australopithecus afarensis","volume":"300","author":"DeSilva","year":"2017","journal-title":"Anat. Rec."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"8151","DOI":"10.1073\/pnas.0812554106","article-title":"Neandertal birth canal shape and the evolution of human childbirth","volume":"106","author":"Weaver","year":"2009","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2031","DOI":"10.1111\/brv.12744","article-title":"The obstetrical dilemma hypothesis: There\u2019s life in the old dog yet","volume":"96","author":"Haeusler","year":"2021","journal-title":"Biol. Rev."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1002\/ajpa.24802","article-title":"There is an obstetrical dilemma: Misconceptions about the evolution of human childbirth and pelvic form","volume":"181","author":"Grunstra","year":"2023","journal-title":"Am. J. Biol. Anthropol."},{"key":"ref_27","first-page":"242","article-title":"The shapes of the female pelvis. Contributing factors","volume":"41","author":"Abitbol","year":"1996","journal-title":"J. Reprod. Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"R921","DOI":"10.1016\/j.cub.2010.10.018","article-title":"Brain development after birth differs between Neanderthals and modern humans","volume":"20","author":"Gunz","year":"2010","journal-title":"Curr. Biol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1064","DOI":"10.1016\/j.jhevol.2008.07.008","article-title":"Brain size at birth throughout human evolution: A new method for estimating neonatal brain size in hominins","volume":"55","author":"DeSilva","year":"2008","journal-title":"J. Hum. Evol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1038\/scientificamerican0960-62","article-title":"Tools and human evolution","volume":"203","author":"Washburn","year":"1960","journal-title":"Sci. Am."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1001\/jama.1961.73040400014011","article-title":"Neonatal and infant immaturity in man","volume":"178","author":"Montagu","year":"1961","journal-title":"JAMA"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"eaaz4729","DOI":"10.1126\/sciadv.aaz4729","article-title":"Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth","volume":"6","author":"Gunz","year":"2020","journal-title":"Sci. Adv."},{"key":"ref_33","unstructured":"Schaal, J.-P., Maillet, R., and Riethmuller, D. (2003). Trait\u00e9 d\u2019obst\u00e9trique, M\u00e9decine-Sciences Flammarion."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1016\/0047-2484(91)90059-5","article-title":"Commonalities in dimorphism and variability in the anthropoid pelvis, with implications for the fossil record","volume":"21","author":"Tague","year":"1991","journal-title":"J. Hum. Evol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1002\/ajpa.1330960204","article-title":"Reconstruction of the Sts 14 (Australopithecus africanus) pelvis","volume":"96","author":"Abitbol","year":"1995","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1159\/000477732","article-title":"Which foetal-pelvic variables are useful for predicting caesarean section and instrumental assistance","volume":"26","author":"Thollon","year":"2017","journal-title":"Med. Princ. Pract."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1002\/ajpa.1330850203","article-title":"Ontogeny and evolution of pelvic diameters in anthropoid primates and in Australopithecus afarensis (AL 288-1)","volume":"85","author":"Abitbol","year":"1991","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1002\/ajpa.1330800108","article-title":"Variation in pelvic size between males and females","volume":"80","author":"Tague","year":"1989","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1055\/s-0038-1668162","article-title":"Change in head shape of newborn infants in the week following birth: Contributing factors","volume":"17","author":"Marchal","year":"2019","journal-title":"J. Pediatr. Neurol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1146\/annurev-anthro-091619-124837","article-title":"The earliest South African hominids","volume":"50","author":"Clarke","year":"2021","journal-title":"Annu. Rev. Anthropol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1002\/ajpa.1330930208","article-title":"Multivariate analysis of the sexual dimorphism of the hip bone in a modern human population and in early hominids","volume":"93","author":"Arsuaga","year":"1994","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_42","unstructured":"Lovejoy, C.O. (1979). A reconstruction of the pelvis of AL-288 (Hadar Formation, Ethiopia). Am. J. Biol. Anthropol., 50."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1407","DOI":"10.1126\/science.1202521","article-title":"A partial pelvis of Australopithecus sediba","volume":"333","author":"Kibii","year":"2011","journal-title":"Science"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1002\/ajpa.1330570402","article-title":"Pliocene hominids from the Hadar formation, Ethiopia (1973\u20131977): Stratigraphic, chronologic, and paleoenvironmental contexts, with notes on hominid morphology and systematics","volume":"57","author":"Johanson","year":"1982","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1002\/ajpa.1330600113","article-title":"Vertebral pathology in the Afar australopithecines","volume":"60","author":"Cook","year":"1983","journal-title":"Am. J. Phys. Anthropol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1006\/jhev.1995.1063","article-title":"Comparison of the pelves of Sts 14 and AL 288-1: Implications for birth and sexual dimorphism in australopithecines","volume":"29","author":"Haeusler","year":"1995","journal-title":"J. Hum. Evol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1016\/j.jhevol.2017.07.014","article-title":"A volumetric technique for fossil body mass estimation applied to Australopithecus afarensis","volume":"115","author":"Brassey","year":"2018","journal-title":"J. Hum. Evol."},{"key":"ref_48","unstructured":"Robinson, J.T. (1972). Early Hominid Posture and Locomotion, University of Chicago Press."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Zipfel, B., Richmond, B.G., and Ward, C.V. (2020). Hominin Postcranial Remains from Sterkfontein, South Africa, 1936\u20131995, Oxford University Press.","DOI":"10.1093\/oso\/9780197507667.001.0001"},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Zipfel, B., Richmond, B.G., and Ward, C.V. (2020). Hominin Postcranial Remains from Sterkfontein, South Africa, 1936\u20131995, Oxford University Press.","DOI":"10.1093\/oso\/9780197507667.001.0001"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1126\/science.1184944","article-title":"Australopithecus sediba: A new species of Homo-like australopith from South Africa","volume":"328","author":"Berger","year":"2010","journal-title":"Science"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1097\/OGX.0b013e3181ecdf0c","article-title":"Assessing cephalopelvic disproportion: Back to the basics","volume":"65","author":"Maharaj","year":"2010","journal-title":"Obstet. Gynecol. Surv."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1146\/annurev-bioeng-061008-124823","article-title":"On the biomechanics of vaginal birth and common sequelae","volume":"11","author":"DeLancey","year":"2009","journal-title":"Annu. Rev. Biomed. Eng."},{"key":"ref_54","first-page":"847","article-title":"Pelvic Dimensions and the outcome of trial labour in Shona and Zulu primigravidas","volume":"55","author":"Stewart","year":"1979","journal-title":"S. Afr. Med. J."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1002\/ajpa.1330750107","article-title":"Evolution of the ischial spine and of the pelvic floor in the Hominoidea","volume":"75","author":"Abitbol","year":"1988","journal-title":"Am. J. Biol. Anthropol."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1016\/S0047-2484(84)80029-9","article-title":"Obstetrical interpretation of the australopithecine pelvic cavity","volume":"13","author":"Berge","year":"1984","journal-title":"J. Hum. Evol."},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Laudicina, N.M., Rodriguez, F., and DeSilva, J.M. (2019). Reconstructing birth in Australopithecus sediba. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0221871"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.jhevol.2016.06.001","article-title":"Virtual reconstruction of the Australopithecus africanus pelvis Sts 65 with implications for obstetrics and locomotion","volume":"99","author":"Claxton","year":"2016","journal-title":"J. Hum. Evol."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/j.jhevol.2006.05.006","article-title":"Chimpanzee neonatal brain size: Implications for brain growth in Homo erectus","volume":"51","author":"DeSilva","year":"2006","journal-title":"J. Hum. Evol."}],"container-title":["Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-7737\/13\/6\/398\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:51:33Z","timestamp":1760107893000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-7737\/13\/6\/398"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,5,31]]},"references-count":59,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2024,6]]}},"alternative-id":["biology13060398"],"URL":"https:\/\/doi.org\/10.3390\/biology13060398","relation":{},"ISSN":["2079-7737"],"issn-type":[{"value":"2079-7737","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,5,31]]}}}