The development of lighter births means slower walks and pelvis

Bekken width can affect the risk of birth complications and back bread

Cavan photos/Getty pictures

The breadth of a person’s hips appears to be a result of complex balances between the development of larger brains and vertical walks, according to the large study of its kind to date.

“If your brain gets bigger and bigger over the same evolutionary time as your pelvis becomes narrower, this results in conflict,” says VagheSh Narasimhan at the University of Texas in Austin.

This idea, first suggested in the 1960s, is known as the obstetric dilemma. Recently, it has been suggested that the risk of pelvic images also factors in. The pelvic floor is a layer of muscles that keep our organs in place. If it weakens or tears, it can lead to incontinence and problem with childbirth.

“The obstetric dilemma has been discussed very hot,” says Narasimhan. There have been Mary earlier studies trying to relate the pelvis’s structure to walking speed and efficiency, for example, but these studies have used a small number of people and produced conflicting results, he says.

Now Narasimhan and his colleagues have used data from UK Biobank to look at 31,000 men and women. The team measured various aspects of the pelvis based on a type of scan called double energy X -ray absorptiometry and looked for correlations with genetic variations and aspects of people’s health, such as demanding emergency.

The results indicate that having a wider pelvis reduces the risk of complications during childbirth, but results in slower walk and a high risk of pelvic floor -related conditions and osteoarthritis of the hip. Meanwhile, a narrower pelvis can accelerate walking, but the risk of birth complications, back pain and knee osteoarthritis.

It has been previously suggested that there is a connection between having narrower hips and previous births to reduce the risk of birth complications, but the team found no correlation between pelvic width and the length of the pregnancies. “This is in line with other studies showing that human children are not born [relatively] Before than in the other great monkeys, ”says Narasimhan.

The team observed a connection between pelvic width and the main size of babies at birth. “Individuals who may be giving birth to children with a wider head of have a wider pelvis,” says Narasimhan. “It happens because we naturally choose for individuals who have this context.” This election may now be completed by C-sections, claimed a 2016 survey.

Another finding is that most people have suffered asymmetrical pelvis that correlates with their hand. Being left or right -handed determines that the leg is dominant, which affects walks and the development of the pelvis, and this can lead to a slight asymmetry when we go, says Narasimhan.

“This is an extraordinary contribution to a basic aspect of human evolutionary biology,” says Scott Simpson at Case Western Reserve University in Cleveland, Ohio. “By integrating anatomical, genetic, clinical and behavioral data, the authors have provided insight into this unique human adaptation.”

“It’s great to be able to utilize large data sets,” says Nicole Webb at the University of Zurich in Switzerland, who has shown that birth channels for chimpanzees are not much wider than humans. Webb points out that all people in the data set were over 40 years old and from the UK. “If this work was done on younger, more different populations, the results could be even more striking,” she says.

Topics:

  • Human development/
  • pregnancy

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