a. Blood Flow.

When the umbilical blood stops flowing at birth, sudden pressure differences occur within the circulatory system.

These differences cause the blood flowing to the lungs and liver to increase and the blood flowing through the bypass channels to decrease.

Peripheral circulation refers to residual cyanosis in hands and feet. This may be apparent for one to two hours after birth and is due to sluggish circulation. Blood is shunted to vital organs immediately after birth.

b. Blood Coagulation.

During the first few days of life, the prothrombin level decreases and clotting time in all infants is prolonged. This process is most acute between the second and fifth postnatal days. It can be prevented to a large extent by giving vitamin K to the infant after birth. With the ingestion of food, establishment of digestion, and maturation of the liver, vitamin K is manufactured by the baby and clotting time stabilizes within a week to ten days.