Physiologic and Behavioral Adaptations of the Newborn

First period of reactivity

– Lasts up to 30 minutes after birth
– Heart rate increases from 160 to 180 beats/min
– Decreases after 30 minutes to baseline
– Infant is alert and has spontaneous startles, crying, and head movement

Period of decreased responsiveness

– Lasts from 60 to 100 minutes
– Infant is pink
– Respirations are rapid and shallow up to 60
breaths/min
– Sleeps or has a marked decrease in motor activity

Second period of reactivity

– Lasts from 10 minutes to several hours
– Occurs between 2 and 8 hours after birth
– Tachycardia, tachypnea occur
– Meconium passed
– Increased muscle tone, changes in skin color, and
mucus production

Initiation of breathing

– Chemical factors
– Mechanical factors
– Thermal factors
– Sensory factors

Respirations

– RR 30-60 breaths/min
– Periodic breathing
– Obligatory nose breathers
– Abdominal breathing
– Signs of respiratory distress –
flaring, retractions, grunting,
tachypnea, central cyanosis

Cardiac changes at birth

– Fetal shunt closure
– HR 120-160 bpm
– regular rate & rhythm
– murmurs are common
– blood pressure
– blood volume
– delayed cord clampin

Red blood cells and hemoglobin

– RBCs, hematocrit, and hemoglobin
increased
– 70% fetal hemoglobin
– Iron stores adequate for 4 months

Leukocytes & Platelets

– Leukocytosis normal at birth
– Susceptible to infection

Platelets
– Same as adult
– Clotting factors require vitamin K

Thermogenesis

– Nonshivering thermogenesis
– Metabolism of brown fat

Hypothermia and cold stress

– Tachypnea / respiratory distress
– Hypoglycemia

Thermogenic System

– Thermoregulation
– Neutral thermal environment (NTE)
– Hyperthermia

Methods of Heat Loss

Conduction

Convection

Evaporation

Radiation

Renal System

– First void by 24 hours
– Excrete 15-60 mL/kg of urine daily
– 6-8 voids/day after 4 days of age
– Straw colored in appearance
– “Brick dust”
– Fluid and electrolyte balance
– Signs of renal system problems

Gastrointestinal System

– Coordinate suck, swallow, and
breathe
– Stomach capacity
– At birth <10 mL
– By 7 days up to 60 mL
– 5-10% weight loss normal

Meconium Stool

– Passed by 24 - 48 hours
– Greenish black
– Thick, tar-like
– No odor
– Not passed
  Obstruction
    Imperforate anus

Transitional Stool

– Passed by third day
– Greenish brown to yellowish brown
– Less thick and sticky

Milk Stool: Breast vs Formula

Breast- loose, more frequent

Formula- more formed, risk for constipation, odor

Mouth

Epstien pearls- normal

Natal teeth- normal, choke risk

Hepatic System

– Iron storage
– Glucose homeostasis
– Fatty acid metabolism
       Bilirubin synthesis
– Pathologic jaundice
– Coagulation
– Drug metabolism
– Signs of hepatic system problems

Jaundice - Hyperbilirubinemia

– Yellow coloring of skin, sclera, oral mucous membranes
– Starts at head and progresses to torso and extremities
– Jaundice will become visible at around 6-7 mg/dL

Jaundice Causes & Risk

– Accelerated destruction of fetal RBCs
– Altered hepatic clearance of bilirubin
– Fewer bilirubin binding sites

– Risk factors – prematurity, ethnicity, breastfeeding

Physiologic Jaundice

– Nonpathologic
– Occurs after 24 hours of age
– Usually resolves without treatment
– Peak of 5-6 mg/dL by 72-96 hours of age
– Resolved by 2 weeks of age

Pathologic Jaundice

– Appears before 24 hours of age
– Rises by more than 0.2 mg/dL per
hour
– Exceeds the 95th percentile on
nomogram
– Persists for more than 2 weeksPathologic Jaundice

Pathologic Jaundice Causes

– Hemolytic disease
– Glucose-6-phosphate dehydrogenase
deficiency

Kernicterus or acute bilirubin
encephalopathy (ABE)

– Hypotonia
– Delayed motor skills
– Hearing loss
– Cerebral palsy
– Gaze abnormalities
– Seizures
– Coma
– Deathencephalopathy (ABE)

Breastfeeding-associated
jaundice

– Early-onset jaundice
– Begins at 2-5 days of age
– Associated with poor feeding

Breast milk jaundice

– Late-onset jaundice
– Begins at 5-10 days
– Peaks during second week then gradually diminishes
– Caused by factors in breast milk

Immune System

– Immunoglobulins
– IgG – crosses plaGenta
– IgM – begiMs at birth
– IgA – breAst milk
– Risk for infection
– Decreased ability to recognize, localize, destroy infection

Integumentary System

– Color
– Bruising
– Sweat glands
– Desquamation (peeling)
– Mongolian spots
– Birth marks
– Rash
– Skin tags

Normal

Vernix Caseosa

Acrocyanosis

Lanugo

Milia

Mongolian Spot

Erythema Toxicum

Nevi/Birthmarks and bruising

Stork bite

Port-wine stain

Strawberry hemangioma- abnormal

Forceps Marks / Bruising

Reproductive System

– Female
– Male
– Swelling of breast tissue
– Signs of risk for reproductive system problems

Skeletal System

– Skull
– Spine
– Extremities
– Signs of risk for skeletal problems

Spine & Extremities

Spina Bifida, skin tag

Extremities- should be flexed

Neuromuscular System

– Responsive and reactive to
environment
– Spontaneous motor activity
– Transient temors
– Persistent tremors
– Seizure activity
– Muscle tone

Newborn reflexes

– Rooting
– Sucking
– Swallowing
– Grasp- Palmar, Plantar
– Moro or “startle”
– Babinski

Behavioral Adaptations

– Sleep-wake states
– Other factors influencing behavior of newborns: 
– Gestational age
– Time
– Stimuli
– Medication

Response to environmental
stimuli

– Temperament
– Habituation
– Consolability
– Cuddliness
– Irritability
– Crying