Care of the Newborn

Abstract

At birth the baby makes a transition from intrauterine to extrauterine existence. Until then the placenta has been functioning as the organ for gaseous exchange, for nutrition, for excretion and for the production of various hormones that are necessary for the maintenance of pregnancy. At the time of birth, or soon thereafter, various physiological systems of the baby take over these functions. Thus respiration is initiated and the function of gaseous exchange is taken over by the lungs. Full expansion of the lungs may not be achieved until several days after birth, especially in the low birth weight baby or the baby whose vitality and strength have been lowered by disease, drugs or anoxia. As the lungs expand and assume function, the pulmonary capillary bed opens up and pulmonary circulation gets established; at the same time the placenta with its vascular structure is removed from the systemic circulation. With better oxygenation in the alveoli of the lungs the oxygen tension of the blood increases. All these factors act as a trigger mechanism which brings about changes in the foetal circulation converting it to the adult type of circulation. Other dormant systems, such as the gastro-intestinal tract and the urinary system also begin to function. Within a day or two of birth, the gastro-intestinal system has to obtain calories and various nutrients essential for the metabolic needs of the body tissues.