Parturition in baboons (PAPIO SPP.)

Schlabritz‐Loutsevitch, Natalia; Mäher, James; Sullivan, Ryan D.; Mari, Giancarlo; Schenone, Mauro; Cohen, Harris L.; Word, R. Ann; Hubbard, Gene B.; Dick, Edward J.

doi:10.1038/s41598-018-19221-4

Cited by 8 publications

(6 citation statements)

References 35 publications

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“…Nevertheless, instances of obstructed labour have been reported for both diminutive marmosets and small‐bodied squirrel monkeys ( Saimiri sciureus ) (Abee, 1989 ; Debyser, 1995 ) as well as medium‐sized macaques ( Macaca mulatta and M. fascicularis ) and baboons ( Papio spp.) (Schultz, 1949 ; Schlabritz‐Loutsevitch et al ., 2018 ). A study on a large sample of captive pigtailed macaques ( Macaca nemestrina ) reported a surprisingly high incidence of difficult births at 14%, while in some captive squirrel monkey populations the occurrence may be as high as 50% (Bowden, Winter & Ploog, 1967 ; Stockinger et al ., 2011 ).…”

Section: The Birth Processmentioning

confidence: 99%

“…Yet, in a captive colony of pigtailed macaques, most birth difficulties turned out to be due to malpresentation, particularly breech positions (Stockinger et al ., 2011 ). Breech presentations were also found to be a major cause (25%) of dystocic births in baboons (Schlabritz‐Loutsevitch et al ., 2018 ), and they seem to explain most birth difficulties in squirrel monkeys and other non‐human primates (Bowden et al ., 1967 ; Stoller, 1995 ).…”

Section: The Birth Processmentioning

confidence: 99%

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The obstetrical dilemma hypothesis: there's life in the old dog yet

et al. 2021

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The term 'obstetrical dilemma' was coined by Washburn in 1960 to describe the trade-off between selection for a larger birth canal, permitting successful passage of a big-brained human neonate, and the smaller pelvic dimensions required for bipedal locomotion. His suggested solution to these antagonistic pressures was to give birth prematurely, explaining the unusual degree of neurological and physical immaturity, or secondary altriciality, observed in human infants. This proposed trade-off has traditionally been offered as the predominant evolutionary explanation for why human childbirth is so challenging, and inherently risky, compared to that of other primates. This perceived difficulty is likely due to the tight fit of fetal to maternal pelvic dimensions along with the convoluted shape of the birth canal and a comparatively low degree of ligamentous flexibility. Although the ideas combined under the obstetrical dilemma hypothesis originated almost a century ago, they have received renewed attention and empirical scrutiny in the last decade, with some researchers advocating complete rejection of the hypothesis and its assumptions. However, the hypothesis is complex because it presently captures several, mutually non-exclusive ideas: (i) there is an evolutionary trade-off resulting from opposing selection pressures on the pelvis; (ii) selection favouring a narrow pelvis specifically derives from bipedalism; (iii) human neonates are secondarily altricial because they are born relatively immature to ensure that they fit through the maternal bony pelvis; (iv) as a corollary to the asymmetric selection pressure for a spacious birth canal in females, humans evolved pronounced sexual dimorphism of pelvic shape. Recently, the hypothesis has been challenged on both empirical and theoretical grounds. Here, we appraise the original ideas captured under the 'obstetrical dilemma' and their subsequent evolution. We also evaluate complementary and alternative explanations for a tight fetopelvic fit and obstructed labour, including ecological factors related to nutrition and thermoregulation, constraints imposed by the stability of the pelvic floor or by maternal and fetal metabolism, the energetics of bipedalism, and variability in pelvic shape. This reveals that human childbirth is affected by a complex combination of evolutionary, ecological, and biocultural factors, which variably constrain maternal pelvic form and fetal growth. Our review demonstrates that it is unwarranted to reject the obstetrical dilemma hypothesis entirely because several of its fundamental assumptions have not been successfully discounted despite claims to the contrary. As such, the obstetrical dilemma remains a tenable hypothesis that can be used productively to guide evolutionary research.

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Section: The Birth Processmentioning

confidence: 99%

Section: The Birth Processmentioning

confidence: 99%

The obstetrical dilemma hypothesis: there's life in the old dog yet

et al. 2021

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“…; Schlabritz‐Loutsevitch et al. ). In humans, 30% of brain development takes place in utero compared to 60% in NHPs, including baboons (DeSilva and Lesnik ; DeSilva ).…”

Section: Discussionmentioning

confidence: 99%

“…Temporal cortex tissue samples were collected immediately from fetuses of control and MNR mothers at 120, 140, and 165 days gestational age (dGA, length of gestation is 163–185 dGA (Schlabritz‐Loutsevitch et al. )) and flash frozen and stored at −89°C until analyzed (Schlabritz‐Loutsevitch et al. ) (Table ).…”

Section: Methodsmentioning

confidence: 99%

Ontogeny and programming of the fetal temporal cortical endocannabinoid system by moderate maternal nutrient reduction in baboons ( Papio spp.)

et al. 2019

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Poor nutrition during pregnancy is a worldwide public health problem. Maternal nutrient reduction ( MNR ) is associated with maternal and fetal stress and a sex‐dependent decrease in nonhuman primate ( NHP ) cognitive performance. Early life stress potentiates epileptogenesis in a sex‐specific manner, and temporal lobe ( TL ) epilepsy is associated with neurocognitive disorders. The endogenous cannabinoid system ( ECS ) demonstrates remarkable developmental changes and plays a key role in aging‐related diseases (e.g., dementia). Baboons have been studied as a natural model of epilepsy and express all ECS system components. We therefore evaluated baboon fetal temporal cortex ECS ontogenic and MNR ‐dependent changes. At 120 days gestational age ( dGA ) (term 185 days), maternal, fetal, and placental morphometry were similar between control and MNR pregnancies. MNR maternal weight gain was decreased compared with controls at 165 dGA independent of fetal sex. In male fetuses, expression of ECS synthesizing and degrading enzymes was gestational age‐dependent, with the exception of fatty acid amide hydrolase ( FAAH ). MNR had a sex‐specific effect on the protein expression of CB 1R during development: CB 1R protein expression was decreased in fetal temporal cortex of male fetuses at 120 and 140 dGA . Our data reveal that the MNR has sex‐specific effects on temporal cortical expression of the ECS in baboon offspring and shows vulnerability of ECS in male fetuses during gestation.

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“…The infrahyoid muscles are also markedly small in infants (Figure 7). Moreover, hypotonia itself has been suggested to be a risk factor for NBPP (Abzug et al, 2019;Abzug & Kozin, 2014;Defrancesco et al, 2019 (Abitbol, 1996;Kavanagh et al, 2011;Rosenberg & Trevathan, 1995;Schlabritz-Loutsevitch et al, 2018;Stockinger et al, 2011)…”

Section: Head Size Neck Muscle Strength and Tonementioning

confidence: 99%

Risk factors for neonatal brachial plexus palsy attributed to anatomy, physiology, and evolution

et al. 2021

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The inherent variable anatomy of the neonate and the uniquely-shaped maternal birth canal that is associated with the evolution of human bipedalism constitute risk factors for neonatal brachial plexus palsy (NBPP). For example, those neonates with a prefixed brachial plexus (BP) are at greater risk of trauma due to lateral neck traction during delivery than those with a normal or postfixed BP. Compared to adults, neonates also have extremely large and heavy heads (high head: body ratio) set upon necks with muscles and ligaments that are weak and poorly developed. Accordingly, insufficient cranial stability can place large torques on the cervical spinal nerves. In addition, the pelvic changes necessary for habitual bipedal posture resulted in a uniquely-shaped, obstruction-filled, sinusoidal birth canal, requiring the human fetus to complete a complicated series of rotations to successfully traverse it. Furthermore, although there are many risk factors that are known to contribute to NBPP, the specific anatomy and physiology of the neonate, except for macrosomia, is not considered to be one of them. In fact, currently, the amount of lateral traction applied to the neck during delivery is the overwhelming legal factor that is used to evaluate whether a birth attendant is liable in cases of permanent NBPP. Here, we suggest that the specific anatomy and physiology of the neonate and mother, which are clearly not within the control of the birth attendant, should also be considered when assessing liability in cases of NBPP.

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Parturition in baboons (PAPIO SPP.)

Cited by 8 publications

References 35 publications

The obstetrical dilemma hypothesis: there's life in the old dog yet

The obstetrical dilemma hypothesis: there's life in the old dog yet

Ontogeny and programming of the fetal temporal cortical endocannabinoid system by moderate maternal nutrient reduction in baboons ( Papio spp.)

Risk factors for neonatal brachial plexus palsy attributed to anatomy, physiology, and evolution

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