Evolution of the human pelvis and obstructed labor: New explanations of an old obstetrical dilemma.

@article{Pavlicev2019EvolutionOT,
  title={Evolution of the human pelvis and obstructed labor: New explanations of an old obstetrical dilemma.},
  author={Mihaela Pavlicev and Roberto J. Romero and Philipp Mitteroecker},
  journal={American journal of obstetrics and gynecology},
  year={2019}
}
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38 Citations
Highly Influential Citations
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Background Citations
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38 Citations

The obstetrical dilemma hypothesis: there's life in the old dog yet
TLDR
This 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 and remains a tenable hypothesis that can be used productively to guide evolutionary research.
The evolution of pelvic canal shape and rotational birth in humans
TLDR
This work shows that the shape of the lower birth canal affects the ability of the pelvic floor to resist the pressure exerted by the abdominal organs and the foetus, and suggests that the anteroposterior oval outlet shape is an evolutionary adaptation for pelvic floor support.
Biomechanical trade-offs in the pelvic floor constrain the evolution of the human birth canal
TLDR
Evidence is presented that a large pelvic floor is disadvantageous for maintaining continence and supporting the weight of the inner organs and the fetus through multiple finite element analyses of pelvic floor models varying in size and thickness, and functional trade-offs affecting not only the size but also the thickness and stiffness of the pelvic floor are observed.
Squatting, pelvic morphology and a reconsideration of childbirth difficulties
TLDR
It is suggested that habitual squatting, together with taller stature and better nutrition of ancestral hunter-gatherers compared with later Neolithic and industrial counterparts, obviated an OD.
Did population differences in human pelvic form evolve by drift or selection?
TLDR
It is proposed that pelvic dimensions have evolved different "compromise solutions" in different populations in response to local selective regimes, and results from a reanalysis of a large published global dataset on human pelvic canal dimensions clearly support this view.
Sex differences in the pelvis did not evolve de novo in modern humans.
TLDR
It is concluded that this pattern of pelvic sex differences did not evolve de novo in modern humans and must have been present in the common ancestor of humans and chimpanzees, and thus also in the extinct Homo species.
Dynamic finite-element simulations reveal early origin of complex human birth pattern
TLDR
It is concluded that australopithecines required cooperative breeding to care for their secondary altricial infants, and these prerequisites for advanced cognitive development seem to have been corollary to skeletal adaptations for bipedal locomotion that preceded the appearance of the genus Homo and the increase in encephalization.
The association of parturition scars and pelvic shape: A geometric morphometric study
TLDR
It is suggested that difficult or prolonged labor may indeed cause more strongly expressed pelvic features, presumably because of increased strain of the pelvic ligaments during birth.
Can the Dynamic External Pelvimetry Test in Late Pregnancy Reveal Obstructed and Prolonged Labor? Results From a Pilot Study
TLDR
Dimension and biomechanical properties of the pelvic tissue and spaces influence the evolutionary childbirth process and hypomobility of specified external pelvic diameters measured in shifting positions can become a screening tool to detect the contracted pelvis and prevent damage caused by dystocia and prolonged labor in women and newborns.
Biomechanical comparison of squatting and "optimal" supine birth positions.
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References

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