What we must remember is that nature is not conscious; the processes that we call Nature do not care what happens to infant or mother or the consequences to our species. The processes roll on without malice or intent; without sympathy or guarantee for successful outcomes.
The difference between Homo sapiens and other apes>primates>mammals> is that reproductive success is selected by the “unforgiving” conditions in nature that produce feedback between environmental pressures and the adaptability of species. A rigorous “shaping” of specific creatures occurs in specific environments.
The fate of Homo sapiens has been drastically removed from this natural regime. We intervene in the failure / success of reproduction without consideration as to the consequences (adaptability) – not even the consequences for a single mother and child are truly considered
It is astounding to consider how many (psychologically juvenalized) American adults DO NOT SEE their infant children as REAL PHYSICAL BEINGS, but as “supernatural” beings sent by god. The enormous technological interventions that keep severely premature infants alive, are “a gift from god”; physicians are “tools” of god; god uses medical technology and personnel and other magic to “heal” the massive insults to the child’s brain development, lung function, digestive system, immune system, muscles and bones and unprepared skin barrier. And everyone will live happily ever after. This is delusional.
The obstetric dilemma: an ancient game of Russian roulette, or a variable dilemma sensitive to ecology?
1Childhood Nutrition Research Centre, UCL Institute of Child Health, London WC1N 1EH, UK. Jonathan.Wells@ucl.ac.uk
The difficult birth process of humans, often described as the “obstetric dilemma,” is commonly assumed to reflect antagonistic selective pressures favoring neonatal encephalization and maternal bipedal locomotion. However, cephalo-pelvic disproportion is not exclusive to humans, and is present in some primate species of smaller body size. The fossil record indicates mosaic evolution of the obstetric dilemma, involving a number of different evolutionary processes, and it appears to have shifted in magnitude between Australopithecus, Pleistocene Homo, and recent human populations. Most attention to date has focused on its generic nature, rather than on its variability between populations. We re-evaluate the nature of the human obstetric dilemma using updated hominin and primate literature, and then consider the contribution of phenotypic plasticity to variability in its magnitude. Both maternal pelvic dimensions and fetal growth patterns are sensitive to ecological factors such as diet and the thermal environment. Neonatal head girth has low plasticity, whereas neonatal mass and maternal stature have higher plasticity. Secular trends in body size may therefore exacerbate or decrease the obstetric dilemma. The emergence of agriculture may have exacerbated the dilemma, by decreasing maternal stature and increasing neonatal growth and adiposity due to dietary shifts. Paleodemographic comparisons between foragers and agriculturalists suggest that foragers have considerably lower rates of perinatal mortality. In contemporary populations, maternal stature remains strongly associated with perinatal mortality in many populations. Long-term improvements in nutrition across future generations may relieve the dilemma, but in the meantime, variability in its magnitude is likely to persist.
Copyright © 2012 Wiley Periodicals, Inc.
The evolutionary origins of obstructed labor: bipedalism, encephalization, and the human obstetric dilemma.
- 1Anthropology, Washington University, St. Louis, Missouri, USA.
Obstructed labor is a common complication of human childbirth. In parts of the world where access to emergency obstetric services is limited, obstructed labor is a major cause of maternal mortality. Women who survive the ordeal of prolonged obstructed labor often end up suffering from an obstetric vesicovaginal fistula or another serious birth injury that leaves them crippled for life. Compared with the other higher primates (chimpanzees, bonobos, gorillas, and orangutans), these problems are uniquely human. This article reviews the evolutionary origins of the human obstetric dilemma with special reference to the changes imposed on pelvic architecture by the assumption of upright, bipedal posture and locomotion. The subsequent development of progressively increasing brain size (encephalization) in hominins led to the present human obstetrical conundrum: how to balance the evolutionary advantage of bigger babies with larger brains against the presence of a narrow pelvis that is difficult for a fetus to traverse during labor.
Clin Perinatol. 2008 Sep;35(3):469-78, ix. doi: 10.1016/j.clp.2008.06.003.
Bipedalism and parturition: an evolutionary imperative for cesarean delivery?
- 1Department of Obstetrics and Gynecology, Division of Reproductive Imaging and Genetics, Maternal Fetal Medicine, Thomas Jefferson University and Hospital, 834 Chestnut Street, Suite 400, Philadelphia, PA 19107, USA. email@example.com
Human biologic evolution involves a compromise between the physical adaptations for bipedalism with effects on birthing success and the much later increases in encephalization of our species. Much of what comes to define life history parameters like gestation length, and brain and birth weight in our species is best understood from this evolutionary perspective. Human populations have been dealing with the obstetric dilemma for many hundreds of thousands of years and modern biomedicine, using techniques like cesarean sections, has alleviated, but not eliminated, birthing as a “scar” of human evolution. If women begin to demand access to universal cesarean delivery, what will the outcome be for the future of human evolution? We can only speculate on the social, biologic, and demographic costs of this transition.