The rise in popularity of C-sections is just one of the many factors why mothers in developed countries are birthing bigger babies.
According to Sapiens, human evolution has been tweaked by the introduction of the C-section, allowing big babies who could not fit through their mother’s pelvis before the ability to come into the world through surgery. Working against natural selection has continued the tread of narrow hipped women and big headed babies that simply can’t be born naturally.
In 1960, anthropologist Sherwood Washburn said humans are known for having big babies with large brains and since mothers began walking upright their hips have become more narrow. These two facts led to a birthing conundrum, especially since Mihaela Pavlicev, an evolutionary biologist, discovered babies thrive being born bigger and mothers do better during birth if they have narrow pelvises.
Karen Rosenberg, a biological anthropologist working at the University of Delaware said that recent choices for diet and exercise among mothers have also contributed to birthing difficulties.
But at the end of the day, babies will not outgrow their mothers. Pavlicev said the maximum size of babies will plateau, because they’re growth is limited by their mother’s metabolism.