Passage through the birth channel exerts significant pressure on the fetal head.
Credit: Ami et al., 201
When infants pass through the mother's birth canal, the tight fit is temporarily squashed by their wee heads, extending their flexible skull and changing the shape of their brains. Now, scientists have created 3D images that show the magnitude of the amazing conformal hair distortion.
Baby's heads can change under pressure because the legs in their skull have not yet melted together, according to the Mayo Clinic. Soft areas on the top of the head can be squeezed through the birth canal and allow space for the brain to grow during infants.
The exact mechanics of how a child's skull and brain change shape during work is not well understood. To learn more about that process, scientists performed magnetic resonance imaging (MR) scans of seven pregnant women: when the subjects were between weeks 36 and 39 of their pregnancies, and then when they were working, after their cervixes were fully extended. [7 Baby Myths Debunked]
Their images revealed significant skull cramps – known as embryonic head casting – in all infants and suggested that the pressure exerted on infant heads and the brain during birth was believed to be stronger than ever, researchers reported in a new study.
In all seven fetuses, the skull bones that did not overlap before the work was visibly overlapped when the work began, deforming infants' heads and brains, the researchers wrote. In five children, the skull returned to its prelaboratory forms shortly after birth, and the deformation was not noticeable when the newborns were examined.
The MRI scans captured views on soft tissue that were not visible by ultrasound, giving important clues to understanding deformation of the fetal skull and brains, and the movement of modern soft tissues around them during birth, according to the study.
The findings were published online today (May 15) in the journal PLOS One.
Originally published on Live Science .