Giving birth feels like a miracle for many reasons, one of which is the way a baby's head squeezes through a mother's narrow birth canal.

Doctors know that this is possible due to the flexible birth canal expanding to make room for the baby's head. As it passes through, the head also temporarily changes shape and becomes elongated to fit into the limited passage.

While these are all well-documented, the exact mechanisms of the process have never been observed in real time nor thoroughly analyzed and understood, until now.

A Peek At Babies' Heads During Childbirth

In a study published in the journal PLOS One, doctors at the University Hospital Center in France sought to shed light on this specific stage of birth by observing seven pregnant women with magnetic resonance imaging. The MRI scans took place twice: between 36 and 39 weeks of their pregnancy, then during labor when their cervixes are already fully dilated.

The results were quite surprising, even for doctors who are aware of the process. All of the infants experienced significant skull squeezing, or also called fetal head molding, which suggests that the pressures on their heads during childbirth are stronger than previously assumed, according to  Live Science.

Bones that did not overlap prior to labor were observed to overlap during labor in all seven infants, which means all of their heads showed deformation during the process. Five of the babies bounced back quickly with their heads returning to their pre-labor shapes soon after delivery.

Pressure on delicate infant heads may sound terrifying, but it's normal and is executed flawlessly in most cases.

Potential Issues

One of the things that the research team focused on is the possible trauma that can occur at this stage of childbirth.

"Sometimes there are brain hemorrhages, and we don't know where (they) are coming from," said study lead author Dr. Olivier Ami to NBC News.

These incidents could result in developmental issues, such as cerebral palsy.

If doctors could predict which babies are likely to experience difficulties in fetal head molding, they could recommend a C-section ahead of time and avoid the danger entirely.

As of now, there is no way to know which babies would have problems and which would not prior to labor. During labor, there is constant monitoring of the infant's heartbeat to detect possible distress.

Ami and the rest of the team hope that they could develop software imaging techniques that could predict susceptibility to these complications.