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Frémondière P, Haeusler M, Thollon L, Webb NM, Marchal F. Obstetrical Constraints and the Origin of Extended Postnatal Brain Maturation in Hominin Evolution. BIOLOGY 2024; 13:398. [PMID: 38927278 PMCID: PMC11201025 DOI: 10.3390/biology13060398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024]
Abstract
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-baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine "dyads" 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 25-28%. 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.
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Affiliation(s)
- Pierre Frémondière
- Faculty of Medical and Paramedical Sciences, School of Midwifery, Aix Marseille University, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France
- UMR 7268 ADES, Aix Marseille University, EFS, CNRS, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France;
| | - Martin Haeusler
- Institute of Evolutionary Medicine, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland;
| | - Lionel Thollon
- LBA, Aix Marseille University, Gustave Eiffel University, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France;
| | - Nicole M. Webb
- Institute of Evolutionary Medicine, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland;
- Department of Palaeoanthropology, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - François Marchal
- UMR 7268 ADES, Aix Marseille University, EFS, CNRS, 51 Boulevard Pierre Dramard, 13344 Marseille CEDEX 15, France;
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Iaconianni JA, Balasubramanian S, Grimm MJ, Gonik B, Singh A. Studying the Effects of Shoulder Dystocia and Neonate-Focused Delivery Maneuvers on Brachial Plexus Strain: A Computational Study. J Biomech Eng 2024; 146:021009. [PMID: 38116838 PMCID: PMC10880949 DOI: 10.1115/1.4064313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/02/2023] [Accepted: 11/05/2023] [Indexed: 12/21/2023]
Abstract
The purpose of this computational study was to investigate the effects of neonate-focused clinical delivery maneuvers on brachial plexus (BP) during shoulder dystocia. During shoulder dystocia, the anterior shoulder of the neonate is obstructed behind the symphysis pubis of the maternal pelvis, postdelivery of the neonate's head. This is managed by a series of clinical delivery maneuvers. The goal of this study was to simulate these delivery maneuvers and study their effects on neonatal BP strain. Using madymo models of a maternal pelvis and a 90th-percentile neonate, various delivery maneuvers and positions were simulated including the lithotomy position alone of the maternal pelvis, delivery with the application of various suprapubic pressures (SPPs), neonate in an oblique position, and during posterior arm delivery maneuver. The resulting BP strain (%) along with the required maternal delivery force was reported in these independently simulated scenarios. The lithotomy position alone served as the baseline. Each of the successive maneuvers reported a decrease in the required delivery force and resulting neonatal BP strain. As the applied SPP force increased (three scenarios simulated), the required maternal delivery force and neonatal BP strain decreased. A further decrease in both delivery force and neonatal BP strain was observed in the oblique position, with the lowest delivery force and neonatal BP strain reported during the posterior arm delivery maneuver. Data obtained from the improved computational models in this study enhance our understanding of the effects of clinical maneuvers on neonatal BP strain during complicated birthing scenarios such as shoulder dystocia.
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Affiliation(s)
- Joy A. Iaconianni
- Drexel University, 3120 Market Street, Bossone 713, Philadelphia, PA 19104
| | - Sriram Balasubramanian
- School of Biomedical Engineering, Drexel University, 3120 Market Street, Bossone 713, Philadelphia, PA 19104
| | - Michele J. Grimm
- College of Nanotechnology, Science, and Engineering, University at Albany, 1400 Washington Ave, Albany, NY 12222
| | - Bernard Gonik
- Obstetrics & Gynecology — School of Medicine, Wayne State University, 3990 John R. Street, 7 Brush North, Detroit, MI 48201
| | - Anita Singh
- College of Engineering, Temple University, Engineering Building Room 601, Bioengineering, 1947 N. 12th Street, Philadelphia, PA 19104
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3
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Laudicina NM, Cartmill M. Clavicle length and shoulder breadth in hominoid evolution. Anat Rec (Hoboken) 2023. [PMID: 36594678 DOI: 10.1002/ar.25144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/23/2022] [Accepted: 12/13/2022] [Indexed: 01/04/2023]
Abstract
For a given body mass, hominoids have longer clavicles than typical monkeys, reflecting the lateral reorientation of the hominoid glenoid. Relative length of the clavicle varies among hominoids, with orangutans having longer clavicles than expected for body mass and gorillas and chimpanzees having shorter clavicles than expected. Modern humans conform to the general hominoid distribution, but Neandertals and Upper Paleolithic Homo sapiens have longer clavicles than expected for their size and exhibit marked positive allometry in clavicle length. Relative to clavicle length, adult and newborn humans have broader shoulders (biacromial breadths) than comparable apes, because the reduced elevation of the human shoulder swings the acromion laterally downward away from the head. Since broadened shoulders yield an increased risk of maternal and neonatal injury and/or death from shoulder dystocia during birth, we might expect hominins to manifest trends toward reduction in shoulder breadth and clavicle length. They do not, presumably because of countering selection pressures favoring a long clavicle in the adults. The marked sexual dimorphism seen in patterns of clavicular growth and static adult allometry in humans suggests that those selection pressures have disproportionately affected the males.
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Affiliation(s)
- Natalie M Laudicina
- Biomedical Sciences, Grand Valley State University, Allendale, Michigan, USA.,Department of Anthropology, Boston University, Boston, Massachusetts, USA
| | - Matt Cartmill
- Department of Anthropology, Boston University, Boston, Massachusetts, USA.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
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Abstract
SignificanceDuring human birth, the risk of complications is relatively high because of the comparatively large dimensions of the fetal head and shoulders relative to the maternal birth canal. Here we show that humans exhibit a developmental mode of the shoulders that likely contributes to mitigating obstetrical problems. Human shoulder growth is decelerated before birth but accelerated after birth, which stands in contrast to the more uniform shoulder growth trajectories of chimpanzees and macaques. This indicates that fetal developmental modifications were required during human evolution not only in the head but also in the shoulders to compensate obstetrical constraints.
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Childbirth and Infant Care in Early Human Ancestors: What the Bones Tell Us. EVOLUTIONARY PSYCHOLOGY 2022. [DOI: 10.1007/978-3-030-76000-7_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Abstract
Humans have a prolonged childhood, which begins with an immature developmental state at birth. We take care of these helpless infants through a variety of cultural adaptations, including material culture, provisioning of food, and shared child care. Our species has long been characterized as having secondary altriciality, but an examination of human life history shows that we are fundamentally precocial, despite seeming helpless at birth. Human babies are also relatively large and overall require substantial attention and energy from caregivers. Previous work has focused on how culture permits us to give birth to helpless young and how our cultural adaptation solves problems stemming from encephalization. The birth of these dependent, costly creatures poses challenges but also creates opportunities by enhancing the development of social and emotional relationships with caregivers as well as language acquisition and enculturation.
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Affiliation(s)
- Karen R. Rosenberg
- Department of Anthropology, University of Delaware, Newark, Delaware 19716, USA
- Philosophical Faculty, University of Hradec Králové, 500 03 Hradec Králové, Czech Republic
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Gunz P, Neubauer S, Falk D, Tafforeau P, Le Cabec A, Smith TM, Kimbel WH, Spoor F, Alemseged Z. Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth. SCIENCE ADVANCES 2020; 6:eaaz4729. [PMID: 32270044 PMCID: PMC7112758 DOI: 10.1126/sciadv.aaz4729] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/09/2020] [Indexed: 05/05/2023]
Abstract
Human brains are three times larger, are organized differently, and mature for a longer period of time than those of our closest living relatives, the chimpanzees. Together, these characteristics are important for human cognition and social behavior, but their evolutionary origins remain unclear. To study brain growth and organization in the hominin species Australopithecus afarensis more than 3 million years ago, we scanned eight fossil crania using conventional and synchrotron computed tomography. We inferred key features of brain organization from endocranial imprints and explored the pattern of brain growth by combining new endocranial volume estimates with narrow age at death estimates for two infants. Contrary to previous claims, sulcal imprints reveal an ape-like brain organization and no features derived toward humans. A comparison of infant to adult endocranial volumes indicates protracted brain growth in A. afarensis, likely critical for the evolution of a long period of childhood learning in hominins.
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Affiliation(s)
- Philipp Gunz
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- Corresponding author.
| | - Simon Neubauer
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
| | - Dean Falk
- Department of Anthropology, Florida State University, Tallahassee, FL 32310, USA
- School for Advanced Research, 660 Garcia St., Santa Fe, NM 87505, USA
| | - Paul Tafforeau
- European Synchotron Radiation Facility, 71 Avenue des Martyrs, CS-40220, F-38043, Grenoble cedex 09, France
| | - Adeline Le Cabec
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- European Synchotron Radiation Facility, 71 Avenue des Martyrs, CS-40220, F-38043, Grenoble cedex 09, France
| | - Tanya M. Smith
- Australian Research Centre for Human Evolution, Griffith University, 170 Kessels Rd., Nathan 4111, Queensland, Australia
| | - William H. Kimbel
- Institute of Human Origins, and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA
| | - Fred Spoor
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
- Centre for Human Evolution Research, Department of Earth Sciences, Natural History Museum, London SW7 5BD, UK
- Department of Anthropology, UCL, London WC1H 0BW, UK
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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Cheyney M, Davis-Floyd R. Birth and the Big Bad Wolf: Biocultural Evolution and Human Childbirth, Part 1. INTERNATIONAL JOURNAL OF CHILDBIRTH 2020. [DOI: 10.1891/ijcbirth-d-19-00030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this two-part article, we reflect on the evolution of human childbirth by combining our respective expertise in folklore and interpretive anthropology (Davis-Floyd) and physiologic birth (Cheyney). In Part 1, we follow six little folkloric pigs from the beginnings of human history through to the present, adapting the well-known tale of “The Three Little Pigs and the Big Bad Wolf.” Using this tale as a metaphorical device, we explore complex relationships between humans and nature, society, and childbirth through a description of the six basic subsistence strategies humans have developed over time—foraging, horticulture, agriculture, pastoralism, industrialism, and the technocracy, reflecting on how these ways of life connect to birthing practices. We argue that despite vast cultural differences in the treatment of birth—including those few cultures where solitary birth is valued—premodern, pre-industrial birthways had much in common, such as labor accompaniment, upright positions, and freedom of movement during labor and birth. These similarities were supplanted during the Industrial Revolution with the subsequent growth of technocratic societies and replaced by an also very similar set of birthing practices. However, these technocratic approaches do very little to support, and often even undermine, our evolved birthing biologies. Throughout, we use the Big Bad Wolf as a metaphor for the wild, untamed, and sometimes intense power of nature (and also of unmedicated birth), and ask, what does the Big Bad Wolf have to teach us about how we support and perform childbirth today?
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Charlier P, Coppens Y, Hassin J. Is the duration of human pregnancy decreasing? A vision of Darwinian medicine. J Matern Fetal Neonatal Med 2020; 35:806-808. [PMID: 32114844 DOI: 10.1080/14767058.2020.1731461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Why do actual females have a 9-months-pregnancy? Here, we hypothesize that the pregnancies of prehuman species were longer than currently (10 or 11 months), and that anatomical and metabolic changes, by increasing the in-utero size of the fetal brain, selected groups with premature delivery, low-calcified and/or not welded cranial vault bones (permitting deformation during the expulsion), until reaching a current pregnancy duration of 9 months.
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Affiliation(s)
- Philippe Charlier
- Department of Research and High Education, Museum of Quai Branly - Jacques Chirac, Paris, France.,Laboratory Anthropology, Archaeology, Biology (LAAB), University Paris Saclay (UVSQ), Montigny-le-Bretonneux, France
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Moving Beyond the Obstetrical Dilemma Hypothesis: Birth, Weaning and Infant Care in the Plio-Pleistocene. THE MOTHER-INFANT NEXUS IN ANTHROPOLOGY 2020. [DOI: 10.1007/978-3-030-27393-4_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Hominin birth mechanics have been examined and debated from limited and often fragmentary fossil pelvic material. Some have proposed that birth in the early hominin genus Australopithecus was relatively easy and ape-like, while others have argued for a more complex, human-like birth mechanism in australopiths. Still others have hypothesized a unique birth mechanism, with no known modern equivalent. Preliminary work on the pelvis of the recently discovered 1.98 million-year-old hominin Australopithecus sediba found it to possess a unique combination of Homo and Australopithecus-like features. Here, we create a composite pelvis of Australopithecus sediba to reconstruct the birth process in this early hominin. Consistent with other hominin species, including modern humans, the fetus would enter the pelvic inlet in a transverse direction. However, unlike in modern humans, the fetus would not need additional rotations to traverse the birth canal. Further fetal rotation is unnecessary even with a Homo-like pelvic midplane expansion, not seen in earlier hominin species. With a birth canal shape more closely associated with specimens from the genus Homo and a lack of cephalopelvic or shoulder constraints, we therefore find evidence to support the hypothesis that the pelvic morphology of Australopithecus sediba is a result of locomotor, rather than strictly obstetric constraints.
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Cofran Z. Brain size growth in Australopithecus. J Hum Evol 2019; 130:72-82. [PMID: 31010545 DOI: 10.1016/j.jhevol.2019.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 01/01/2023]
Abstract
Postnatal growth is one of the proximate means by which humans attain massive adult brain size. Humans are characterized by the maintenance of prenatal brain growth rates into the first postnatal year, as well as an overall extended period of growth. The evolution of this pattern is difficult to assess due to its relatively brief duration and the underrepresentation of well-preserved fossil individuals who died during this short period. In this study, I use Monte Carlo methods to reconstruct postnatal brain growth rates in Australopithecus afarensis and Australopithecus africanus, based on estimates of neonatal brain size and of likely brain size and age at death of infant specimens (A.L. 333-105, DIK-1-1, and Taung). Neonatal brain size is reconstructed from the empirical scaling relationship among catarrhines which humans follow, and conservative estimates of fossils' chronological ages and brain sizes are drawn from the literature. Simulated distributions of these values are used to calculate average annual rates (ARs) of brain growth and proportional size change from birth (PSC), which are compared to resampled statistics from humans, chimpanzees and gorillas of known age and sex. Simulated ARs and PSCs for A. afarensis are significantly lower than those of chimpanzees and gorillas. Both ARs and PSCs for A. africanus are similar to chimpanzee and gorilla values. These results indicate that although these early hominins were derived in some aspects of brain anatomy, high rates of brain growth did not appear until later in human evolution. Moreover, findings also imply that brain growth rates are not a simple function of adult brain size. This study provides important new information about the evolution of brain growth, despite limitations inherent in fossil samples.
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Affiliation(s)
- Zachary Cofran
- Anthropology Department, Vassar College, 124 Raymond Avenue, Box 42, Poughkeepsie, NY 12603, USA.
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13
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Beaudet A, Du A, Wood B. Evolution of the modern human brain. PROGRESS IN BRAIN RESEARCH 2019; 250:219-250. [DOI: 10.1016/bs.pbr.2019.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Rosenberg KR, Trevathan WR. Evolutionary perspectives on cesarean section. EVOLUTION MEDICINE AND PUBLIC HEALTH 2018. [DOI: 10.1093/emph/eoy006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Karen R Rosenberg
- Department of Anthropology, University of Delaware, Newark, DE 19716, USA
| | - Wenda R Trevathan
- Department of Anthropology, New Mexico State University, Las Cruces, NM 80003, USA
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Rosenberg KR, DeSilva JM. Evolution of the Human Pelvis. Anat Rec (Hoboken) 2017; 300:789-797. [PMID: 28406563 DOI: 10.1002/ar.23580] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 12/12/2022]
Abstract
No bone in the human postcranial skeleton differs more dramatically from its match in an ape skeleton than the pelvis. Humans have evolved a specialized pelvis, well-adapted for the rigors of bipedal locomotion. Precisely how this happened has been the subject of great interest and contention in the paleoanthropological literature. In part, this is because of the fragility of the pelvis and its resulting rarity in the human fossil record. However, new discoveries from Miocene hominoids and Plio-Pleistocene hominins have reenergized debates about human pelvic evolution and shed new light on the competing roles of bipedal locomotion and obstetrics in shaping pelvic anatomy. In this issue, 13 papers address the evolution of the human pelvis. Here, we summarize these new contributions to our understanding of pelvic evolution, and share our own thoughts on the progress the field has made, and the questions that still remain. Anat Rec, 300:789-797, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Karen R Rosenberg
- Department of Anthropology, University of Delaware, Newark, Delaware
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire
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