The reason babies cry when they are born into the world:
1. Cries of Communication
Apparently that is a reaction that will signify its response to differences in the inner and outer world of the womb. One of them is the difference in temperature in the womb (36-36.5C) and the room temperature is usually lower. His response to the new environment is a clue that the baby is in good condition. As is known by everyone that the baby can only communicate with his parents only through crying, because the baby's cry that is heard at birth is one form of communication from the baby.
2. Respiratory cries
First breathing occurs due to mechanical stimulation when the baby's chest is depressed as it passes through the birth canal. The main thing is of course chemical stimulation when the baby's body feels the need for air supply for its metabolic processes. Then the air will immediately fill air pockets in the lungs called alveoli.
If the newborn does not cry immediately, the doctor will immediately suspect that the respiratory system does not work properly. This means that there is something abnormal with his lungs. It could be because the lungs of the baby have not been fully formed, have abnormalities or are infected with amniotic fluid.
3. Crying Activities
Crying at birth is known to help the activity of the baby's own body, because when crying automatically the baby will move. In the Journal of Child Psychology and Psychiatry, the researchers used functional MRI scans to see the reactions of 12 women after hearing the baby first cry for 30 seconds. The scan results show that the baby's cry is able to regulate activities in various regions of the mother's brain, one of which is the amygdala, which is the part that plays a role in regulating maternal emotions.
So it's natural that the newborn baby immediately cries, because that is the first time the baby can see the world.