A new study suggests that the process of giving birth can be difficult for women because the pelvis is designed to stand upright.
The study, which was published in the journalBMC Biology , relies on computer-generated simulations of how bone soft tissue and skin work in tandem as we move. The same method has been used to identify key factors of a flawless baseball fastball and the best marathon gait.
Researchers used digital images to examine how the pelvis and bones move during daily activities and birth. Because the shape of the human pelvic canal does not allow for a quick or easy birth, the researchers wanted to know if its dimensions were linked to some other human characteristic.
This canal is simple and oval in the apes. Thus labor and delivery could be easier for these species. However, the oval in the human canal is shaped differently through the pelvis, requiring babies to turn during birth to ensure that their head and shoulders can pass through.
Computer-generated models using digital images suggested that the strain and pressure of being upright on two legs could give the pelvic canal its twist. Researchers used an oval that was consistently aligned, similar to one that apes use and the pelvis sank and destabilized their spine. This made it difficult to keep a steady balance on two feet.
Our balance might be even better with a widened outlet in the lower part of the birth canal, investigators discovered. A wider outlet can make childbirth injuries more likely because it will require an even harder twist of the shoulders and head within the canal. The authors suggest that the shape of the pelvic canal may be an “evolutionary compromise” between these competing factors.
These findings are based on computer models based on digital images, and do not precisely recreate the evolutionary or birthing process. However, they do provide another feature to consider when answering the question of why human labor and delivery are so difficult, when compared with our closest living relatives.
BMC Biology “The evolution in pelvic canal shape, and rotational birth in people.”
News release, University of Vienna.
Content Source: https://www.medscape.com/viewarticle/963024?src=rss