Hematopoietic Adaptations of the Newborn

What is the average blood volume of a full-term infant?

80-90 mL/kg

What determines the newborn’s blood volume?

Timing of cord clamping

At birth blood transfers from the placenta to the newborn

Benefits of delayed cord clamping

Additional blood transfer from the placenta to the fetus, can significantly increase blood volume.

• Reduce risk for anemia

• Enhanced pulmonary perfusion

• Additional iron stores

• Increased H&H

Disadvantages of delayed cord clamping

Increased risk of jaundice

• Higher volume of erythrocytes

• polycythemia

  • an elevated red blood cell count (hematocrit > 65%), can lead to hyperviscosity, thickening the blood and hindering oxygen delivery

Erythrocytes and Hemoglobin in an infant

• Newborn has greater erythrocytes and increased H&H than an adult

• HbF slowly replaced by HbA

• HbF carries more O2 than HbA

• HbF has a shorter lifespan (90 days)

Hemolysis in the newborn

HgB is broken down and bilirubin is released.

Risk of jaundice

WNL Hct in newborn

46-68%

What impacts hematocrit in the infant

Vary according to age and volume transfused (delayed cord clamping)

Polycythemia

• Abnormally high RBC count

  • risk for jaundice & organ damage

    • increased viscosity of RBCs

  • Risk of hypoglycemia

  • Risk of resp distress

Sign of Polycythemia

Ruddy color or reddish skin

Leukocytes of a newborn

An elevated leukocyte count in a normal newborn does not always indicate infection

During first 12 hours, leukocytes remain elevated before they begin to decline

WNL WBC infant

9100-30000

Leukocytes and infection in the newborn

Decreased leukocytes

Increased number of immature leukocytes

Decrease in platelets

What is absent in the newborn?

Vitamin K

What does the absence of Vit K put the infant at risk for?

Blood-clotting deficiency

How is clotting facilitated in the infant?

IM injection of vitamin K phytonadione (AquaMEPHYTON)

Prevention of hemorrhagic disease