Is it instinct, reflex or biological response of a newborn to cry

The cry of the newborn actually serves the purpose of a strong respiratory effort.During foetal life (i.e., inside the uterus) the lungs of the foetus are filled with fluidand do not take part in the respiratory process.

Though the foetus does makerespiratory movements the lungs remain collapsed.At this stage the placentaacts as the ‘foetal lung,’ supplying the foetus with oxygen and removingcarbon dioxide.

At birth the placental circulation is cut off and the infant experiences increasingasphyxia.Finally, the infant gasps several times, and the lungs expand.

Considerable amount of pressure is needed in the lungs to overcome the fluidforces and inflate the lungs for the first time.The markedly negative intrapleuralpressure during the gasps contributes to the expansion of the lungs.

The fluid inthe lungs is partly extruded from the mouth and partly absorbed by the lymphchannels.

With the first inspiration the lungs expand with air and the gas exchangefunction is transferred from the placenta to the lungs.

There is a scoring system — the APGAR score — which is used to assess the newborn. In it a good cry is taken as a sign of good respiratory effort.