Study Notes on Preterm and Postterm Newborns
Chapter 13: Preterm and Postterm Newborns
Gestational Age
Definition: Actual time from conception to birth that the fetus remains in the uterus.
Classification of newborns based on gestational age:
Preterm infant: Less than 37 weeks gestation.
Early term infant: Between 37 weeks, 0 days and 38 weeks, 6 days.
Full term infant: Between 39 weeks, 0 days and 40 weeks, 6 days.
Late term infant: Between 41 weeks, 0 days and 41 weeks, 6 days.
Postterm infant: Born at 42 weeks, 0 days and beyond.
Estimation of Gestational Age
Ballard scoring system:
Total of 12 scores determines maturity rating expressed in weeks of gestation.
Performed within the first few hours after birth and repeated at 24 hours.
Neuromuscular Maturity
Score Metrics for evaluation:
Posture: Observations regarding extremity positions.
Square window (wrist): Measure flexibility at the wrist.
Arm recoil: Assess ability to recoil arms post extension.
Popliteal angle: Evaluate knee flexibility.
Scarf sign: Presence or absence of arm crossing beyond the neck.
Neuromuscular maturity scores contribute to gestational age assessment.
Physical Maturity
Lanugo: Presence and density.
Skin characteristics:
Amount of subcutaneous fat, thickness, and condition (e.g. wrinkled).
Breast development: Stage of areola presence and development.
Eye/Ear: Evaluation of eyelid fusion and pinna development.
Genital development:
Assessment of male and female genital characteristics.
The Preterm Newborn
Characteristics:
Born before 37 weeks gestation.
Often shows:
Wrinkled skin covered with lanugo fine hair
Thin body with little subcutaneous fat.
Prominent fontanelles and sutures of the skull.
Weaker cry indicating poor muscle tone.
Appearance: Limp body with extremities in extension rather than flexion.
Complications:
Most common factor associated with neonatal death.
Increased risk of birth defects; mortality linked to lower birth weight.
Causes of Preterm Birth
Contributing factors include:
Multiple births (twins)
Maternal illness ( iron deficiency anemia)
Hazards of pregnancy (e.g., gestational hypertension).
Placental abnormalities:
Placenta previa.
Premature separation of the placenta from the uterine wall.
Respiratory System of the Preterm Newborn
Maturity Timeline:
Respiratory system not fully mature until after the 35th week.
Surfactant presence aids in lung function, critical for alveolar stability.
THis is why betamethazone is given
Increased risk of alveolar collapse if born before 35 weeks, leading to:
Reduced gas exchange (oxygen and carbon dioxide).
Hypoxia and decreased pulmonary blood flow, exhausting newborn energy.
Breathing Patterns in the Preterm Newborn
Characteristics:
Irregular breathing patterns termed periodic breathing.
Risk for apnea; significant apneas (>20 seconds) can lead to bradycardia and cyanosis.
Susceptibility to gastroesophageal reflux due to a weak gag reflex.
Risks of laryngospasms and aspiration exist due to weak respiratory muscles.
Signs of Respiratory Distress in Preterm Newborn
Common observable signs:
Retractions of the chest wall.
Expiratory grunting.
Nasal flaring.
Changes in respiratory and heart rates.
Respiratory passages may be occluded by mucus plugs, exacerbated by high-oxygen therapy and ventilatory support, potentially leading to bronchopulmonary dysplasia (BPD) or retinopahty (blindness)
Sepsis in the Preterm Infant
Definition: Generalized infection of the bloodstream.
Risk factors due to immature immune systems:
Immature liver leading to poor antibody production.
Inefficient body enzymes.
Symptoms include:
Low temperature.
Lethargy or irritability.
Poor feeding.
Respiratory distress.
Treatment of Sepsis in Neonates
Involves:
Administration of intravenous antimicrobials.
Maintenance of warmth and nutrition.
Close monitoring of vital signs.
Care should promote conservation of energy for the infant.
Adherence to Standard Precautions, including strict hand hygiene, is essential.
Other Complications of Preterm Birth
Bronchopulmonary dysplasia: Lungs become stiff and non-compliant.
Intraventricular hemorrhage: Occurs in the fragile vessels of the preterm infant's brain.
Retinopathy of prematurity: Abnormal growth of retinal blood vessels correlated with oxygen use.
Patent ductus arteriosus: Failure of ductus arteriosus closure postnatally. incase ductus arteriosus does not close
Necrotizing enterocolitis: Ischemic damage to GI mucosa potentially leading to bowel perforation.
Nursing Care for Body Temperature Control
Importance of monitoring:
Core temperature may not reflect skin temperature initially.
Utilization of skin probes placed in the right upper quadrant of the abdomen.
Placement under radiant warmer or incubator as necessary.
Hypoglycemia in Newborns
Defined as plasma glucose levels:
<40 mg/dL in term infants.
<30 mg/dL in preterm infants.
Pathophysiology:
Preterm infants have not gestated long enough to store sufficient glycogen and fat, leading to higher metabolism demands not met by stored resources.
Hypocalcemia in Newborns
Calcium transport through the placenta is critical, especially in late gestation when needs are highest.
Early hypocalcemia: Related to parathyroid gland's inability to initiate calcium release in response to low levels.
Late hypocalcemia: Associated with cow's milk feedings leading to increased phosphate levels, which decrease serum calcium levels.
Nursing Care for Necrotizing Enterocolitis
Critical care steps include:
Monitoring vital signs rigorously.
Measuring abdomen size and auscultating bowel sounds.
Carefully resuming fluids as per physician orders.
Implementing infection prevention measures.
Potential surgical intervention for necrosed bowel.
Family Reaction to Preterm Infant
Emotional impact on parents:
Need for guidance during hospitalization due to feelings of guilt or blame.
Concerns about capacity to care for an extremely small infant.
Educational components include:
Providing appropriate stimulation techniques without tiring the infant.
Thermoregulation in Incubation
Focus on maintaining stable body temperature.
Importance for survival and care of preterm infants:
Nurse's knowledge of using various incubators for effective care is essential.
Nursing Care Related to Nutrition
Tasks include:
Observing bowel sounds and meconium passage.
Gavage feeding practices: Aspiration of gastric contents before feeding.
Deciding to withhold feeding based on residual content levels and notifying healthcare providers as necessary.
Positioning and Nursing Care
Positioning guidance:
Newborns should be in neutral flexion with limbs close to the body.
Recommended positions: Side or prone with slightly elevated head position in supervised settings only.
Benefits:
Reduces respiratory effort and promotes oxygenation.
Encourages organized sleep patterns and minimizes energy expenditure.
Recommendations against prolonged positioning to prevent skin breakdown.
Prognosis for Preterm Infant
Growth trends:
Growth rates may reach those of term infants by the second year.
Very-low-birthweight infants might not catch up if there are chronic illnesses or inadequate nutritional support.
Developmental assessment:
Calculation of growth and development based on current age minus weeks preterm.
The Postterm Newborn
Definition: Infants born beyond 42 weeks of gestation.
Placental Function: Diminishes after a certain gestational age, leading to concerns for fetal well-being.
Related risks:
Increased mortality and morbidity rates compared to term infants.
Problems Associated with Postterm Delivery
Potential complications:
Asphyxia.
Meconium aspiration.
Poor nutritional status.
Increase in erythrocyte production.
Challenging deliveries due to larger fetal size.
Increased risks of defects and seizures.
Physical Characteristics of the Postterm Newborn
General appearance:
Typically long and thin; may have lost weight.
Loose skin, particularly around thighs and buttocks.
Minimal lanugo and vernix caseosa present.
Observably dry skin that may crack or peel; fingernails may be stained with meconium.
Notably thick head of hair and an alert demeanor.
Transporting the High-Risk Newborn
Critical steps for safe transport:
Stabilization of the newborn before transport.
Collection of baseline data (vital signs, blood work) for transport team.
Ensure accurate identification for both infant and mother.
Allow parents to spend moments with their infant before transport if possible.
Discharge of the High-Risk (Preterm Birth) Newborn
Parents must demonstrate care routines before discharge:
Home nursing visits may be organized for assessment.
Discussions about newborn behavior and setting realistic expectations.
Maintain communication with hospital via “warm lines” for ongoing support.
Referrals for social services and support groups recommended, as well as CPR training review.