Developed by D. Ann Currie, RN, MSN
Physiological Responses of
the Newborn to Birth
 Respiratory Adaptations:
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Mechanical changes
Chemical changes
Thermal changes
Sensory changes
Fetal and Neonatal
Circulation
Normal Term Newborn
Cord Blood
Neutral Thermal
Environmental Temperatures
Physiologic Adaptations
to Extrauterine Life
Newborn Urinalysis Values
Cardiovascular Adaptations
 Decreased pulmonary vascular resistance and
increased blood flow
 Increased systemic pressure and closure of ductus
venosus
 Increased left atrium and decreased right atrium
pressure
 Closure of foramen ovale
 Reversal of blood flow through ductus arteriosus
and increased PO2
 Closure of ductus arteriosus
Transitional circulation:
conversion from fetal to
neonatal circulation.
Fetal-neonatal circulation. A, Pattern of
blood flow and oxygenation in fetal
circulation. B, Pattern of blood flow and
oxygenation in transitional circulation of
the newborn. C, Pattern of blood flow and
oxygenation in neonatal circulation.
Fetal Laboratory
Value Changes
 Decreased erythropoietin production
 Rise of hemoglobin concentration
 Physiologic anemia of infancy
 Leukocytosis
 Decreased percentage of neutrophils
Thermogenesis in
the Newborn
 Large body surface area compared to mass
 Types of heat loss
 Convection
 Radiation
 Evaporation
 Conduction
Convection
Radiation
Evaporation
Conduction
Types of Bilirubin
 Unconjugated bilirubin
 Conjugated bilirubin
 Total bilirubin
Conjugation and
Excretion of Bilirubin
 Bilirubin is transported in blood via albumin
 Bilirubin is transferred into the hepatocytes
 Attachment of unconjugated bilirubin to glucuronic
acid
 Excreted into bile ducts, then into the common duct
and duodenum
 Bacteria transform it into urobilinogen and
stercobilinogen
 Bilirubin is excreted in urine and stool
Jaundice
Physiologic Jaundice
 Accelerated destruction of fetal RBCs
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Increased amounts of bilirubin delivered to
liver
Inadequate hepatic circulation
 Impaired conjugation of bilirubin
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Defective uptake of bilirubin from the
plasma
Defective conjugation of the bilirubin
Physiologic Jaundice
(continued)
 Increased bilirubin reabsorption
 Defect in bilirubin excretion
 Increased reabsorption of bilirubin from the intestine
Liver Adaptations
 Iron content stored in liver
 Low carbohydrate reserves
 Main source of energy is glucose
 Liver begins to conjugate bilirubin
 Lack of intestinal flora results in low levels of
vitamin K
GI Adaptations
 Sufficient enzymes except for amylase
 Digests and absorbs fats less efficiently
 Salivary glands are immature
 Stomach has capacity of 50-60 mL
 Cardiac sphincter is immature
Fluid and Electrolyte
Balance
 Less able to concentrate urine
 Limited tubular reabsorption of water
 Limited excretion of solutes
 Limited dilutional capabilities
Immunologic Responses
in the Newborn
 IgG – passive acquired immunity via placenta
 IgM – usually not passively transferred
 Elevated levels may indicate fetal antigenic activity in
utero
 IgA – passive acquired immunity via colostrum
Periods of Reactivity
 First period of reactivity
 Sleep phase
 Second period of reactivity
Mother and baby gaze at each other. This quiet
alert state is the optimal state for interaction
Behavioral and Sensory
Capabilities
 Habituation
 Orientation
 Auditory
 Olfactory
 Tasting and Sucking
 Tactile
End of Part 1