Obstetrical Theory

1294 Words 5 Pages
In this article, the timing of parturition is discussed in the human primate and a new theory is proposed on why human neonates are born so helpless while neonates of other primates are much more prepared for the world. The article presents the old idea coined the ’obstetrical dilemma’, which supports the idea that humans are born before their brains reach optimal development because if the neonatal head got any larger, it would not be able to fit down the narrow human birth canal. Human birth canals are so narrow in order to support narrow hips that allow efficient upright movement. The new hypothesis presented by the article is that humans give birth when the mother’s metabolic resources are over stressed by the fetus’ metabolic needs and …show more content…
The article presents a comparative approach that looks at challenges of the obstetrical dilemma and findings that support the energetics of gestation and growth hypothesis. At the beginning, the article systematically goes through each supporting piece of evidence for the obstetrical dilemma and provides findings that suggest the evidence is not valid. Ideas that are evaluated are that human gestation is shorter than needed, human fetuses receive less maternal investment than expected during gestation, and that walking upright efficiently requires narrow pelvises and therefore narrow birth canals. Evidence against each of these ideas is presented and statistical analysis of comparative data across other primate species is used to disprove the …show more content…
Comparative analysis was especially used when presenting information that contradicted the ideas of the obstetrical dilemma hypothesis. This analysis included controlling for variables and the n and r2 values were given for each analysis. This is indicative of a high quality paper whose results can be trusted. The only negative point to be made is when the paper disproves the obstetrical dilemma hypothesis with regards to the mechanics and energetics of locomotion. One of the supporting studies used against the hypothesis included a study on pelvic shape and locomotor cost. In the study, 15 men and women were used. An experimental unit of 15 is not very large and the data may not be as accurate as the study suggests. This reduces the authenticity of their claims against this part of the hypothesis, but as a whole the paper used sufficient statistics to support their

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