The Late Preterm Infant
(34 0/7 to 36 6/7 weeks)
Physical Exam
&
Physiologic Challenges
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Why is this a problem?
• The Late Preterm Infant (LPTI) population has
increased by 30% since the 1980’s and accounts for
as much as 75% of all preterm births in the US.
• Possibly due to increasing maternal age, increased
use of fertility treatments, multiple gestation,
increasing obesity rates, maternal morbidity.
• One study reports that a cost of $51,600 is
associated with each late preterm birth.
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Physical Exam Findings
• LPTI should essentially have a normal exam,
but may have some of these variations:
– Increased lanugo, increased vernix, thin appearing
skin, more visible veins
– Boys may have high rising testes and a smoother
appearing scrotum
– Girls may have more prominent labia minora
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Physical Exam Findings
–
–
–
–
Decreased creases on soles of feet
Lack of fully developed cartilage in ear
Decreased subcutaneous fat
May have decreased tone, with resting tone not in
flexed position
• Most of the differences between a full term
and late preterm infant are things you can’t
see during a routine physical exam!
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Risks to the Late Preterm Infant
• Excessive sleepiness
• Excessive weight
loss
• Feeding problems
• Hyperbilirubinemia
• Hypoglycemia
• Respiratory distress
• Sepsis
• Hypothermia and
temp instability
• ED visits and
readmissions
• Development delay
• Increased medical
costs
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Physiologic Challenges:
Thermoregulation
• Increased risk for COLD STRESS:
– Less subQ fat to insulate and less brown
fat/adipose tissue to generate heat
– Immature skin does not function well as a barrier
for evaporative heat loss
– High surface area to body mass ratio
– Higher metabolic rate and little reserve
– Less muscle tone and activity
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Cold Stress
• Can lead to metabolic acidosis, increased
metabolic rate, pulmonary vasoconstriction
• Signs and symptoms may include: apnea,
bradycardia, lethargy, poor tone, mottled or
pale skin.
• May contribute to poor transitioning and lead
to unnecessary sepsis work ups.
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Minimizing Cold Stress
• Goal: neutral thermal environment in which
infant maintains temp without increased O2 or
glucose/energy demand.
• Drying skin and hair with warm blankets after
delivery and placing skin to skin
• Swaddle in 2-3 blankets
• Use of hats
• Use radiant warmer as needed
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Thermoregulation:
Clinical Pathway Interventions
• Increased frequency of VS and temp checks
• Ensure neutral thermal environment
• Frequent skin to skin
– If not skin to skin, keep infant dressed with hat on
and wrapped in 1-2 blankets
• Continue delayed 1st bath
• Hypothermia: slow rewarming with radiant
warmer, check blood sugar.
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Physiologic Challenges:
Breathing
• Development of terminal air sacs in the lungs
continues in utero during weeks 34-36 6/7.
• Alveoli are maturing and becoming lined with Type 1
epithelial cells. These cells are closer in proximity to
capillaries to help with gas exchange.
• Type 2 cells develop during this time also to secrete
surfactant.
• Immaturity can lead to poor lung compliance and
increased pulmonary resistance.
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Physiologic Challenges:
Breathing
• Less effective clearance of amniotic fluid
• Difficult to maintain alveolar expansion
• More likely to experience RDS, TTN, even
respiratory failure.
• Other risks include apnea, bradycardia,
ALTE’s, SIDS
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Respiratory Distress
• Usually manifests in first hours after birth with
grunting, flaring, tachypnea, retractions.
• Risk increases if c-section delivery with no
labor.
– During labor, catecholamines are released which
help with absorption of lung fluid and surfactant
release helping to improve lung compliance.
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Breathing:
Clinical Pathway Interventions
• More frequent VS and respiratory assessments
• Pulse ox screenings with VS
• Parent education regarding respiratory
distress
• If RR >60 breathes per minute, consider
holding feeding temporarily
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Physiologic Challenges:
Energy and Metabolism
• Regulation of temperature helps minimize risk
of hypoglycemia
• All babies have physiologic nadir of blood
sugar between 1-2 hours of life. This
decrease in blood sugar is more pronounced
in the late preterm than full term infant.
• Should have blood sugars monitored and have
first feeding within 1 hour of life (if stable)
and no less than every 3 hours after
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Physiologic Challenges:
Hypoglycemia
• LPTI 3x more likely to suffer from
hypoglycemia than term infants.
• Decreased glycogen stores and adipose tissue
• Immature liver enzymes less able to increase
glucose production through gluconeogenesis
• Immature pancreatic beta cells may secrete
more insulin than necessary
• Medical complications increasing demand.
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Hypoglycemia
• Sources vary as to what is a ‘normal’ glucose in
infants. Reported ranges: 40-45 to 55-70.
• 80% of total glucose is consumed by the brain
• LPTIs cannot effectively use other forms of fuel
such as ketones, amino acids, and glycerol to raise
blood sugar.
• This, combined with immature protective systems in
the brain, make the LPTI more at risk for adverse
neurologic outcomes related to hypoglycemia.
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Energy and Metabolism:
Clinical Pathway Interventions
• Hypoglycemia protocol
• Assess weight loss daily
• Assess ability to eat safely: coordination of
suck, swallow, breathe.
• Early and effective feedings
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Physiologic Challenges:
Feeding & Nutrition
• Risk for poor feeding & inadequate caloric intake
– Mom at risk for delayed/low milk production, weak
suck, small mouth, high energy demand with low
stores, sleepy, uncoordinated
suck/swallow/breathe, lack of hunger cues,
ineffective milk transfer.
• These mother baby dyads need extra help:
– Assistance with latch, education on frequency of
feeding and hunger cues, use of nipple shield,
pumping, supplementing.
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Feeding and Nutrition:
Clinical Pathway Interventions
• Early and effective feedings with assessment
of milk transfer
• Initiate feeding plan based on infants method
of feeding. Feeding plan for discharge.
• Assist mother with learning to pump.
• Early supplementation or increased caloric
formula for excessive weight loss as indicated
in feeding plan
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Physiologic Challenges:
Hyperbilirubinemia
• LPTIs have a later peak (day 5-7) and
prolonged phase of elevated bilirubin.
– Low milk intake and transient slower intestinal
motility leads to slowing passage of meconium
– This increases enterohepatic circulation and
reuptake of bilirubin
– Bilirubin conjugating enzyme activity is lower
• Increased risk of readmission for jaundice.
• Risk of kernicterus is higher
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Minimizing Hyperbilirubinemia
• Optimize feeding with increased milk intake
– Consider early supplementation
– Assist with meconium clearance
– Prevent excessive weight loss
• Keep moms and babies together and
maximize stay in hospital
• Monitor with TC or serum bilirubin checks
• Start phototherapy at a lower threshhold.
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Hyperbilirubinemia:
Clinical Pathway Interventions
• Serum bilirubin at 24 hours of life (obtain with
newborn screen).
• Early and effective feedings
• Daily assessment of jaundice with clinical
assessment and TC/serum checks
• Maximize length of hospital stay
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Physiologic Challenges:
Immature Nervous System
• Significant brain growth and maturation occurs in
last 6-8 weeks of pregnancy
– 34 weeker has 50% less brain volume than term infant
• LPTI less able to control state regulation and
regulate internal processes.
– Decreased tone, positional apnea, disorganized
suck/swallow/breathe, frequent startling, more spitting
up, unpredictable response to stimuli (even when
attempting to soothe)
– Minimizing or clustering stimulation is helpful
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Physiologic Challenges:
Immature Nervous System
• Because of the significant amount of brain
growth, neuronal connections to be made,
and overall nervous system development that
still is occuring, the LTPI is at a higher risk for
long term neurodevelopmental delays.
• In severe cases, IVH and PVL, although this is
not common
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Immature Nervous System:
Clinical Pathway Interventions
•
•
•
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Encourage skin to skin
Minimize unnecessary stimulation
Allow uninterrupted periods of rest
Parent education of behavioral states, infant
soothing techniques, developmental
milestones, etc.
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Physiologic Challenges:
Immature Immune System
• Less maternal antibody transfer across
placenta as compared to full term infant.
• Other risk factors are common to all infants,
although preterm infants more susceptible.
– Chorioamnionitis, ROM >18h, maternal fever.
• Signs and symptoms can be vague.
– Temp instability, respiratory distress,
hypoglycemia, lethargy, jaundice, irritability,
feeding difficulties.
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Immature Immune System:
Clinical Pathway Interventions
• Handwashing!
• GBS protocol
• Evaluate maternal and infant risk factors that
may predispose infant to infection
• No sick contacts
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LPTI Discharge Considerations:
Suggestions from the AAP
• Demonstrate weight gain
• Competent feeding by parents preferred method
• Able to maintain body temperature while dressed
in open crib with normal room temp
• Stable cardiorespiratory function
• Parents educated on special needs of LPTI and
competent in all care
• PCP identified and close follow up arranged
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Additional UNC LPTI Discharge
Considerations
• Discourage any discharge prior to 48 hours of
age.
• Feeding plan in place prior to going home
• Late preterm specific parent education
• PCP follow up within 24 (or 48) hours of
discharge required.
• Consider outpatient follow up with LC 24-48
hours after discharge.
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References
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Darcy, A. (2009). Complications of the Late Preterm Infant. Journal of
Perinatal Neonatal Nursing , 23 (1), 78-86.
Hubbard, E., Stellwagen, L., & Wolf, A. (2007). The Late Preterm
Infant: A Little Baby with Big Needs. Contemporary Pediatrics .
Mally, P., Bailey, S., & Hendricks-Munoz, K. (2010). Clinical Issues in the
Management of Late Preterm Infants. Current Problems in Pediatric and
Adolescent Healthcare , 40 (21), 218-233.
National Guideline Clearinghouse. (2010). Assessment and Care of the
Late Preterm Infant. Evidence-based clinical practice guideline.
Oklahoma Infant Alliance. (2010, September). Caring for the Late
Preterm Infant. A Clinical Practice Guideline.
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References
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University of California, San Diego Medical Center. (2006, October).
Late Preterm Infant Policy Statement.
Raju, T., Higgins, R., Stark, A., & Leveno, K. (2006). Optimizing Care
and Outcome for Late-Preterm (Near Term) Infants: A Summary of the
Workshop Sponsored by the National Institute of Child Health and
Human Development. Pediatrics (118), 1207-1214.
Ramachandrappa, A., & Jain, L. (2009). Health Issues of the Late
Preterm Infant. Pediatric Clinics of North America (56), 565-577.
Verklan, M. T. (2009). So, He's a Little Premature...What's the Big Deal?
Critical Care Nursing Clinics of North America , 21, 149-161.
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