Birth canals of women all over the world may vary in size and shape, and this may prompt health risks as most of the medical textbooks and training are based on European bodies. In the report published in the journal Proceedings of the Royal Society of London B, the variations of width and depth of a pelvic canal may determine the route of a newborn, thus forcing a birth to comply into a standard model might be harmful to the mother as well as the baby.
Lia Betti, the lead author of the study, said obstetricians are being trained using a model based on the pelvis of European women. However, a typical childbirth pattern and a pelvic shape can differ among populations - so this must be updated, particularly in the multiethnic society.
For instance, women from Sub-Saharan Africa have a deeper canal, while Native American women have a wider one. Asian and European women, on the other hand, fall in between. As per the South China Morning Post, this is a crucial matter upon giving birth because the baby usually rotates while traveling through the canal, aligning to the shoulders and head to the channel's contours.
The movement of the baby might be different from the expected pattern, especially if the mother's birth canal is not similar from the model described in textbooks, Betti added, who is also a senior lecturer in evolutionary anthropology at the University of Roehampton in London. She further mentioned some cases from the early-to-mid 20th century of "terrible consequences," in which infants were rotated during delivery using forceps - but only based on "erroneous assumptions" of the pelvis' shape.
Meanwhile, x-raying pregnant women could help determine the position of the baby and also presents data on variations of female's anatomy. About 300,000 women die during or after giving birth every year, and the majority of the cases are due to "complications from delivery." One of the complications is that humans have big brains encased in bone. Hence, Betti explains, the fetus needs to do a series of rotations to navigate the birth canal of the mother.
Betti also noted that the main cause of the variation is probably be related to human migration. Homo sapiens originated in Africa, before being scattered rapidly different continents 60,000 to 100,000 years ago. The contours and shape of a pelvic remain far more distinct in Sub-Saharan Africa than elsewhere. Therefore, women's birth canal variations had been shaped by past population history.
