Increased instances of C-sections are causing evolutionary changes

via popsugar.com

"A small team of researchers with members from Austria and the U.S. has found statistical evidence that an increase in the number of mothers giving birth via C-section over the past several decades has been causing an evolutional change—babies' heads are getting bigger, even as the birth canal size remains fixed. The team has published the results of their analysis in Proceedings of the National Academy of Sciences.

Scientists have known for quite some time that humans have more trouble giving birth than most other animals—this is because of the passage of proportionally larger babies' heads through a relatively small birth canal. 

When a baby has a head that is too big to pass through (known as fetopelvic disproportion), surgeons manually remove the baby through an incision in the mother's lower abdomen—a procedure known as a Cesarean or C-section (believed to be named after Julius Caesar, who was thought to have been cut from his dying mother's womb.)

But what is the evolutionary impact of resorting to C-section every time a baby cannot fit through its mother's birth canal? The researchers with this new effort believe it has led to even more babies being born with over-large heads. They used logic and math to come to this conclusion..."

Learn more:http://medicalxpress.com/news/2016-12-instances-c-sections-evolutionary.html