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Cesarean Births Could Be Affecting Human Evolution, Study Says (bbc.com)
CanadianRealist writes: Larger babies delivered by cesarean section may be affecting human evolution. Researchers estimate cases where the baby cannot fit down the birth canal have increased from 30 in 1,000 in the 1960s to 36 in 1,000 births today, [according to estimates from researchers at the University of Vienna in Austria.] Science Alert reports: "In the past, larger babies and mothers with narrow pelvis sizes might both have died in labour. Thanks to C-sections, that's now a lot less likely, but it also means that those 'at risk' genes from mothers with narrow pelvises are being carried into future generations. More detailed studies would be required to actually confirm the link between C-sections and evolution, as all we have now is a hypothesis based on the birth data." Agreed, more studies required part. Cesareans may simply be becoming more common with "too large" defined as cesarean seems like a better idea. It's reasonable to pose the question based simply on an understanding of evolution. Like it's reasonable to conjecture that length of human pregnancy is a compromise between further development in utero, and chance of mother and baby surviving the delivery.
Babies have been getting bigger for a long time.
This is well documented in medical literature:
- "These findings suggest that US and Canadian babies are getting bigger" https://www.ncbi.nlm.nih.gov/p...
- "We conclude that Canadian infants are getting bigger" https://www.ncbi.nlm.nih.gov/p...
- "Results presented in this study demonstrate that even when migratory effects are eliminated, a secular increase in birth weight is observed" https://www.ncbi.nlm.nih.gov/p...
foo mane padme hum
Sorry but that is currently impossible to test because their are insufficient babies born from IVF that have actually reached adulthood to really analyse that.
I would note that Louise Brown has had two children conceived naturally and her sister Natalie has had four children all conceived naturally. For those ignorant of the facts Louise Brown was the first IVF child in the world and her sister was the fortieth born four years later.
Note that shows the low levels of IVF babies being born in the early years of the technology and why there are too few IVF born adults to really conduct any study into their fertility.
Who would want to go through surgery if they didn't have to, and then go through a year long period of recovery?
Apparently, at least 3%...that's just the number that were granted, not the number who requested it.
http://www.cosmopolitan.com/he...
Just another day in Paradise
This study appears to have multiple flaws: 1) A statistical increase in Caesareans does not mean a statistical narrowing of the pelvis. There is not a causal relationship. This is like suggesting that because relatively fewer people are having their wisdom teeth extracted today, our mouths must be getting bigger. 2) Even with a correlation between pelvis width and Caesareans, it does not mean those children or mothers would have died in non-surgical child birth. This is creating a binary relationship out of a correlation - or in other terms assuming the absence of a negative is a positive. Other factors: - The general guideline today (as I understand it) is that if you have had a Caesarean in the past it is safer to have Caesareans for future babies - this alone might account for the statistical increase. - Larger babies can be attributed to better prenatal health and nutrition. - The increase in Caesareans can be attributed to more women giving birth in a hospital setting where Caesarean is an available and safe option.
I'm curious about the vagina stretching.
Rule 34...
No sig today...
My wife says that childbirth (4 kids, so it`s a relatively good sample) is nothing compared to either kidney stones or appendicitis. There, stop propagating that myth, it`s not that bad.