This is an interesting concept that came up one evening on call. Why do humans have such complicated deliveries? Although most deliveries proceed easily and mimic thousands of years before modern medicine, there is the disturbing fact that the C-section rate in the United States is over 30%. Our labor abnormalities are numerous: arrest of descent, failure to progress, preterm delivery. Furthermore, newborns don't even look like they're ready for the world. They have no way of escaping predators, caring for themselves, scavenging food, or communicating effectively. A newborn human without a caring mother will die. We are incredibly vulnerable and dependent.
In comparison, animals can't do C-sections. Any sort of labor abnormality has been weeded out by evolution. They give birth just fine. And their offspring are surprisingly able. Horses walk right at birth; according to Wikipedia, a foal will stand up and nurse within an hour, trot and canter after a few hours, and gallop by the next day. A joey (newborn kangaroo) is born almost in a fetal state, blind, furless, the size of a jellybean yet is still able to crawl into its mother's pouch.
Why? Why do humans have such difficulty in labor and such vulnerability after delivery whereas animals do not? Are these issues related? One hypothesis is that humans develop a proportionally large brain in utero compared to animals. With the evolution of using hands and language, the cranium has to get larger and larger. The trade off is that if the head is too big, the mother can't deliver the baby. So here we have two opposing forces (reflecting Richard Dawkins' Selfish Gene): the fetus, who wants to develop a giant head in utero versus the mother who has to deliver the fetus before it gets too large. Thus, we get the two problems that aren't seen in animals: difficulty delivering and newborns who are vulnerable and dependent.
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2 comments:
While I agree with your general points, I wonder what percentage of the "labor abnormalities" are generated by the medicalization of pregnancy, labor and delivery? Many other western nations have lower C-Section rates and lower mortality rates associated with pregnancy. Do you think that the US has gone too far down this path?
With that said, I think that modern medicine is a wonderful thing and that well trained OBs can make the difference between miracles and tragedy.
I am impressed with your thoughtful posts on this topic and I do hope you will consider becoming an OB
I completely agree - I think the U.S. has "medicalized" the process too much. The introduction of fetal heart monitoring doesn't seem to improve outcomes; instead, it has only lead to a higher C-section rate.
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