- An SGA infant is one whose length, weight, and had circumference are below the 10th percentile of the normal variation for gestational age as determined by neonatal examination.
- The SGA infant may be preterm, term, or post-term.
- Maternal conditions associated with SGA babies include:
Fetal conditions associated with SGA infants include:
- Hypertension (chronic or pregnancy- induced)
- Cardiac, pulmonary, or renal disease
- Diabetes mellitus (classes D,E,F, and R)
- Poor nutrition
- Use of alcohol, tobacco, or drugs
- Multiple gestation
- Placental insufficiency
- Placental fetal abnormalities
- Pregnancy occurred at high altitudes
The effect of these factors upon the fetus is dependent on the stage of fetal development.
- Normal genetically small infant
- Chromosomal abnormality
- Congenital infections, especially rubella and cytomegalovirus
- Early gestation is a time of rapid cell proliferation. An insult at this time results in organs that contain normal size cells, but they are fewer in number. Infants are symmetrical (their heads and bodies grew proportionately) but their organs are smaller. Usually these infants have a poor prognosis and may never catch up.
- Later in gestation, growth of the fetus results from an increase in cell size. An insult at this time results in organs with a normal number of cells that are smaller in size and causes asymmetric growth. These infants have appropriate-sized heads and body lengths, but their weight and organ sizes are decreased. These infants usually have a better prognosis since they have an adequate number of cells. Their growth catches up if they are provided with good nutrition postnatally.
1. Clinical manifestations
- Soft tissue wasting and dysmaturity
- Loose, dry, and scaling skin
- Perinatal asphyxia (due to a small placenta that is less efficient in gas exchange)
- Plethora, respiratory distress, and central nervous system (CNS) aberrations (if the infant has polycythemia)
- Congenital anomalies (occurring in as many as 35% of SGA infants who suffered insults early in gestation)
2. Laboratory and diagnostic study findings
- Glucose testing will reveal decreased glycogen stores, which increases the potential for hypothermia and hypoglycemia.
- Hematocrit level may be increased (65%), which indicates polycythemia as a result of chronic fetal hypoxia.
- Provide adequate fluid and electrolytes and nutrition.
- Provide a high calorie formula for feeding (more than 20 calories per ounce) to promote steady weight gain (15 to 30 grams per day growth plotted on curves shows a normal growth rate).
Decrease metabolic demands when possible.
- If the infant is breast feeding, add human milk fortifier to expressed breast milk.
- Provide small frequent feedings.
- Provide gavage feedings if the infant does not have a steady weight gain.
- Provide a neutral thermal environment.
- Decrease iatrogenic stimuli.
Maintain a neutral thermal environment. Monitor serum hematocrit (normal is 45% to 65%).
- Monitor glucose screening.
- Provide early feedings.
- Provide frequent feedings (every 2 to 3 hours)
- Administer IV glucose if blood sugar does not normalize with oral feedings.
- If an initial high hematocrit was obtained by heel stick capillary sample, a follow-up sample should be done by venipuncture.
- Observe for signs, symptoms, and complications of polycythemia
- Ruddy appearance
- Lethargy, jitteriness, and seizures
Assess the prenatal history for possible toxoplasmosis, rubella, cytomegalovirus, and herpes simplex infections during pregnancy. Assess maternal and infant antibody titers. Use isolation precautions when congenital infections are suspected. Provide education and emotional support.
- Provide adequate hydration to prevent hyperviscosity
- Explain the possible causes of intrauterine growth retardation.
- Inform parents of the infant’s goal weight for discharge.
- Provide instruction on managing the infant at home.
- Explain how to prepare a higher calorie formula or breast feeding.
- Explain the importance of follow-up with a developmental specialist who will screen for milestone achievements.