Physiologic and Behavioral Adaptations of the Newborn PPT

What major physiologic adjustments must a newborn make after birth?

• Initiate and maintain respirations

• Adjust to circulatory changes (closure of shunts)

• Regulate body temperature

• Ingest, retain, and digest nutrients

• Eliminate wastes

• Regulate weight and maintain glucose levels

What are the three behavioral tasks of newborn adaptation?

1. Regulate behavioral tempo (self-arousal, sleep-wake patterns)

2. Process and organize multiple stimuli

3. Establish a relationship with caregivers and the environment

What occurs during the first period of reactivity?

• Lasts ~30 minutes after birth

• Newborn is alert, active, strong suck

• HR ↑ to 160–180 then falls to baseline (~100–120 bpm)

• Respirations irregular (60–80/min), fine crackles possible

• Good time for bonding and initial breastfeeding

What happens during the period of decreased responsiveness?

• Lasts ~60–100 min

• Infant sleeps or has decreased activity

• HR and RR drop to baseline

• Difficult to arouse; minimal interest in feeding

What marks the second period of reactivity?

• Occurs between 4–8 hours after birth, lasts 10 min–several hours

• Period of alertness and increased muscle tone

• Meconium often passed; may have mild mucus vomiting

What stimulates the newborn’s first breath?

• Chemical (catecholamines ↑ CO₂, ↓ O₂, ↓ pH)

• Mechanical (chest recoil after compression in birth canal)

• Thermal (sudden temperature change at delivery)

• Sensory (light, touch, noise stimuli)

What are normal newborn respiratory characteristics?

• Rate 30–60 breaths/min

• Periodic breathing (normal pauses < 20 sec)

• Nose breathers; chest and abdomen move together

• No grunting, nasal flaring, or retractions (normal signs of distress if present)

What major circulatory changes occur after birth?

• Closure of foramen ovale (functional within 1–2 h)

• Closure of ductus arteriosus (within hours to days)

• Closure of ductus venosus (clamping cord stops placental blood flow)

• HR 110–160 bpm (normal)

Why do newborns have higher RBC and hemoglobin levels than adults?

A greater oxygen carrying capacity is needed for fetal tissue oxygenation in utero.

What are normal newborn hematologic values?

• Hgb 14–24 g/dL (at birth); Hct 44–64%

• WBC 9,000–30,000 /mm³ first day

• Platelets 150,000–300,000 /mm³

Why are newborns prone to heat loss?

• Thin subcutaneous fat and blood vessels close to skin

• Large body surface area to weight ratio

• Cannot shiver effectively

• Lose heat via evaporation, conduction, convection, radiation

What are normal temperature ranges and methods of heat production?

• Axillary temp 36.5–37.5 °C (97.7–99.5 °F)

• Heat generated by non-shivering thermogenesis from brown fat

How soon should a newborn void, and what is normal urine output?

• Should void within 24 hours of birth (usually within 12 h)

• 6–8 wet diapers/day by day 4–5

• Urine may contain uric acid crystals (“brick dust”) first days

When should the newborn pass the first stool, and what type is it?

• Within 24–48 hours after birth

• Thick, sticky, green-black meconium stool

What are the main functions of the newborn liver?

• Bilirubin conjugation (prevent jaundice)

• Glucose regulation (maintain BG > 40 mg/dL)

• Iron storage and clotting factor production (vit K dependent)

Why are newborns at high risk for infection?

• Immature immune system

• Limited antibody production until 3 months

• Passive IgG from mother (last ~3 months post-birth)

• Risk factors: prematurity, chorioamnionitis, maternal fever, PROM, invasive procedures

What are common normal newborn skin findings?

• Vernix caseosa, lanugo

• Milia, erythema toxicum, mongolian spots

• Acrocyanosis (hands & feet bluish first 24 h)

What are normal transient reproductive findings in newborns?

• Male: swollen scrotum, descended testes, possible hydrocele

• Female: labial swelling, mucoid or bloody discharge (“pseudomenstruation”)

• Breast swelling (both sexes) due to maternal hormones

What should the nurse assess in a newborn’s skeletal system?

• Symmetric movements of all extremities

• Fontanels (soft, flat — posterior closes by 2 mo; anterior by 18 mo)

• Possible molding and overriding sutures (normal)

What reflexes are tested to assess neurologic function?

• Moro, rooting, suck, palmar/plantar grasp, Babinski, stepping, tonic neck

• Presence and symmetry indicate intact neurologic status

What are the six newborn sleep-wake states?

• Deep sleep

• Light sleep

• Drowsy

• Quiet alert

• Active alert

• Crying

What sensory abilities are present at birth?

• Vision (focus 8–12 in on faces)

• Hearing (well developed by birth)

• Smell (identifies mother’s breast milk)

• Taste (prefers sweet)

• Touch (sensitive to pain and pressure)

Which factors influence a newborn’s behavioral responses?

• Gestational age, stimuli, medications from labor, time since feeding, state of sleep-wake cycle

Why does thermoregulation present a challenge for newborns?

• Thin subcutaneous fat → poor insulation

• Large body surface area → rapid heat loss

• Inability to shiver effectively