
3D imaging of fetal head molding and brain shape changes during labor - okket
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215721
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pimlottc
Hats off to the women who agreed to give birth inside a MRI for this study.
Wow!

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rolleiflex
One of the evolutionary theses about why our brains are at the size they are,
and no larger / smaller is that we’ve hit the hard limit on what can exit a
female body without killing either the parent or the baby. This paper adds a
lot of credence to that theory.

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sokoloff
Sounds plausible. I have an extended family member who was born after a multi-
day labor [in the 40s] where the doctor asked of the father “do you want the
baby or your wife to go home, because they’re not both going to make it”. He
picked his wife; his wife picked the baby; both went home, but my aunt had
life-long deficits from the multi-day traumatic labor and a forceps
extraction.

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miemo
thank god they picked both

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londons_explore
If I'm reading this right...

Skull and brain is crushed during natural birth, but usually recovers its
normal size afterwards.

I wonder if 'lack of crushing' can be bad for C-section births?

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SketchySeaBeast
> I wonder if 'lack of crushing' can be bad for C-section births?

I don't think they mentioned anything about anything in the "pro" for the
deformation - in fact "These MRI findings suggest that the fetus is subjected
to greater stress than previously thought, which could explain the high
incidence of asymptomatic brain hemorrhages and retinal hemorrhages found
after normal vaginal delivery."

This is something we've adapted to deal with, it's not an ideal event.

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londons_explore
Thats what I mean - there might be benefits too. For example, a bit of
crushing might trigger damage-response in the brain which leads to more
growth.

Since this has been the case for millions of years, evolution might well use
what appears to be a disadvantage as an advantage in some cases. Just like
there are some kinds of tree which grow better with occasional forest fires.

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SketchySeaBeast
There may be, but we'll need evidence for that. Right now we just see the
trauma. Not everything that nature does is a benefit - evolution is a
pragmatist. Our bipedal nature and need for a big brain requires certain
sacrifices to be made. Our ability to make our skulls deform enough to give
birth is the only evolutionary advantage it needs to give us to justify it -
it's hard to survive as a species if you can't give birth. I wouldn't make a
jump to "cesareans are bad" just because it may be right, especially without
any evidence from this evidence being for that, and the evidence against being
"brain trauma".

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officialjunk
My medical friends say that csection births can have complications with fluids
not draining fully from the respiratory system and sinuses etc leading to
infections. This is one benefit of the squishing during natural birth to help
squeeze out fluids where it is no longer needed. Sorry I don’t have anything
to cite.

edit: misspelled “birth”

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lurquer
That's bizarre! A lot of my friends coincendtslly had babies around the same
time. The C-section babies were adorable with perfectly round heads, while the
vaginals looked like Kanamits (obscure Twilight Zone reference).

Of course, all the strange-shaped heads morphed back to normal after a few
weeks.

(What was particularly odd was one friend whose vaginal baby's head was, like
a C-section baby, perfectly spherical... a few crude jokes were made regarding
the implications...)

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Raphmedia
That's to be expected. It's how births are. When babies pass through the
mother's birth canal, the tight fit temporarily squashes their heads,
elongating their flexible skulls and changing the shape of their brains. The
child with a round head either went through a wider birth canal or was
smaller. Joking about a woman's genitalia postpartum is simply distasteful.

