Although births in the water were already celebrated among the ancient Egyptians, there is currently a new trend towards this practice. In warm water, the mother can exert pressure more easily and withstand pain better.
When the baby arrives, it appears underwater, but does not drown. At least not as one might suppose. The reason is that, just at birth, the baby has the so-called "immersion reflex", which will prevent you from trying to breathe underwater.
As he explains Iris Hammelmann in his book How much does a cloud weigh? He explains it like this:
Tiny receptors on your skin, especially in the area of the upper lip and nose, to perceive contact with water send a signal to the brain and it reacts by ordering the occlusion of the respiratory organs to prevent the entry of water into lungs. Simultaneously, the heart rate is reduced, and blood flow is concentrated mainly in the trunk, where the vital organs are located. Because of these precautions, the body needs considerably less oxygen than usual. The reflex ensures that the newborn can remain safely under water for a few seconds.
A few weeks after delivery, the reflex continues to exist, but decreases as it grows if it is not practiced on a regular basis. That is, it is another of those skills that we lose shortly after birth, such as the ability to drink and breathe simultaneously due to the position of our larynx (the subsequent displacement will cause us to choke, but in return it will allow us to emit more articulated sounds ).
However, despite the fashion, the latest reviews of studies on water birth, conducted by the AAP (American Academy of Pediatrics) and ACOG (American College of Obstetricians and Gynecologists), concludes that water birth is discouraged because of the risk to the lives of newborns.