Small for Gestational Age (SGA)

Birthweight Variations

• Fetal growth is influenced by maternal nutrition, genetics, placental function, and environment
• Newborns are classified by birthweight and weeks of gestation

Etiologies of Small Size for Gestational Age at Birth

• Potential maternal factors include young or advanced age, short stature, and cigarette smoking
• Potential fetal factors include chromosomal abnormalities, congenital infections, and metabolic disorders
• Placental abnormalities include avascular villi, infectious villitis, and tumors

Small for Gestational Age (SGA)

• Newborns weighing less than 2,500 g (5lb 8oz) at term are considered SGA.
• Classified as SGA if birthweight is at or below the 10th percentile for gestational age.
• Infants can be preterm, term, or post-term
• Some are constitutionally small and healthy
• Some SGA newborns have Fetal Growth Restriction (FGR), increasing morbidity or mortality
• FGR results from malformations, infections, or uteroplacental insufficiency

SGA Characteristics

• Disproportionately large head compared to body
• Wasted appearance of extremities
• Reduced subcutaneous fat stores
• Jitteriness secondary to hypoglycemia
• Decreased breast tissue
• Scaphoid abdomen (sunken appearance)
• Temperature instability
• Wide skull sutures from inadequate growth

SGA Nursing Management

• Obtain weight, length, and head circumference, comparing to standards
• Monitor feeding tolerance, sucking, and swallowing
• Monitor vital signs for respiratory distress
• Initiate early, frequent oral feedings unless contraindicated
• Newborns' glucose level is about 70% of the maternal glucose level
• Neonatal hypoglycemia greatly injures brain since it needs continuous glucose for energy
• Stressed newborns use glucose stores quickly and have hypoglycemia
• Plasma glucose concentration is at or below 40mg/dL
• Give oral or intravenous feedings with 10% dextrose to maintain glucose at 40mg/dL

Large for Gestational Age (LGA)

• Describes newborns whose birthweight is above 90th percentile and more than 4,000 g (8lb 13 oz) at term
• Vaginal birth may be difficult and result in injury
• Shoulder dystocia, clavicular fractures, and facial palsies are common
• Cesarean birth is common to avoid arrested labor

LGA Maternal Factors

• Factors include diabetes mellitus, multiparity, post-term gestation, and maternal obesity
• Others include paternal height, gestational weight gain, and male fetus

LGA Characteristics

• Have large bodies; appear plump and full-faced

LGA Nursing Management

• Monitor blood glucose levels within 30 minutes of birth, repeating the screening every hour
• Prevent hypoglycemia using formula, breastmilk, or IV glucose
• Monitor and record intake/output and daily weights to evaluate nutritional intake

Gestational Age Variations

• Preterm: infant born before 37 completed weeks
• Late preterm: infant is born near-term between 34 0/7 to 36 6/7 weeks
• Full term: infant is born at 38 through 41 completed weeks
• Postterm: infant is born at 42 weeks or more

Post-term Newborn (Post-mature Infant)

• Placenta providing adequate oxygen and nutrients past 42 weeks is compromised, leading to mortality and morbidity
• After 42 weeks, the placenta ages, deposits fibrin and calcium, hemorrhagic infarcts occur, and blood vessels degenerate
• Fetus uses stored nutrients and wastes, leading to muscle mass and subcutaneous fat loss

Characteristics of Post-term Newborns

• Newborns have dry, cracked, peeling, wrinkled skin
• They have limited/absent vernix caseosa and lanugo
• They often present with long, thin extremities
• Creases cover their entire soles and have wide-eyed, alert expressions
• Abundant hair on scalp and thin umbilical cord present
• Long fingernails and meconium-stained skin and fingernails

Post-term Nursing Management

• Birth of newborn requiring special care was not anticipated in most situations
• Postterm newborns are susceptible to birth challenges secondary to placental dysfunction
• This places them at risk of perinatal asphyxia, hypoglycemia, and respiratory distress from placental deprivation or oligohydramnios compression

Preterm Newborn

• Immature body systems affect transition from intrauterine to extrauterine life, leading to risks/complications

Preterm Physical Characteristics

• Birthweight is less than 5.5 lb and the newborn has a scrawny appearance
• Disproportionately larger head than chest circumference
• Present with poor muscle tone and flexion
• Fontanels are wide and soft with overriding sutures
• Limited subcutaneous fats and undescended testes
• Newborns have plentiful lanugo (soft, downy hair) especially over the face and back
• Poorly formed ear pinna, soft pliable cartilage, fused eyelids, and prominent clitoris/labia minora in females

Preterm Newborn Characteristics

• Matted scalp hair (woolly) and few creases in soles and palms
• Minimal scrotal rugae are apparent in male infants
• The thin, transparent skin with visible veins; breast and nipples not clearly delineated
• Abundant vernix caseosa present

Preterm Respiratory system

• Surfactant deficiency can lead to respiratory distress syndrome
• Unstable chest wall may lead to atelectasis
• Immature respiratory control centers may lead to apnea
• Smaller respiratory passages lead to increased risk for obstruction
• Fluid from passages leads to transient tachypnea

Preterm Gastrointestinal System

• Lack of neuromuscular coordination needed to maintain suck, swallow, and breathing
• Shunting of blood from gut to heart and brain may create ischemia/damage in abdominal walls
• Babies have small stomach capacity, weak abdominal muscles, and compromised metabolic function
• Limited ability to digest proteins and absorb nutrients with weak/absent suck-and-gag reflex
• Can contribute to malnutrition and weight loss

Preterm Renal System

• Immature system reduces ability to concentrate urine, which slows the glomerular filtration rate
• Risk for fluid retention/electrolyte disturbances increases and drug toxicity results from limited ability to clear drugs
• Immature immune system increases susceptibility to infection
• IgG deficiency occurs because transplacental transfer does not occur until after 34 weeks gestation

Preterm Central Nervous System

• Difficulty regulating temperature and stability because they lose heat due to inadequate subcutaneous fats
• Lack of muscle tone and flexion to conserve heat, and immature temperature-regulating center in brain, and inadequate brown fats to generate heat
• Susceptible to hypoglycemia due to immature glucose control mechanism
• Decreased glucose stores and reduced availability of alternative fuels like ketone bodies

Preterm Nursing Management

Promoting Oxygenation

• Lacks surfactant, which lowers surface tension in the alveoli and stabilizes to prevent collapse
• Limited ability to retain air due to insufficient surfactant
• Develop atelectasis quickly leading to hypoxemia, decreased oxygen, acidosis, and hypercarbia
• Treatment goals are to prevent neonatal death and adverse long-term neurodevelopmental sequelae and administer oxygen

Maintaining Thermal Regulation

• Four mechanisms for heat transfer and ways to prevent loss:
  • Convection: heat loss through air current (avoid drafts near the newborn)
  • Radiation: heat loss without direct contact (keep isolettes away from cold sources and provide insulation to prevent heat transfer)
  • Conduction: heat loss through direct contact which means warm everything the newborn comes in contact with
  • Evaporation: heat loss by conversion of liquid into vapor .
• Observe for clinical signs of cold stress like respiratory distress or cyanosis
• Educate parents the need to maintain the newborn temperature and demonstrate safeguard warmth and prevent heat loss

Promoting Nutrition and Fluid Balance

• Most newborns born after 34 weeks gestation can feed orally without significant complications
• Patients born before 34 week gestation typically need Parenteral begin parenteral nutrition within the first 24 hours
• Introduce Entral nutrition and advance based on the degree of maturity and clinical condition. Enteral nutrition replaces parenteral nutrition
• Measure daily weight and monitor intake to identify growth