SGAIUGR

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SGA/IUGR

• Sue Ann Smith, MD
• Neonatologist
• Doernbecher Neonatal Care Center

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Intrauterine Growth Restriction (IUGR)

• No universal definition
• Any baby who does not achieve intrauterine growth
  potential
• Usually defined as lt 2 SD below the mean for
  weight.

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Small for Gestational Age (SGA)

• Usually defined as lt2SD or lt10th for growth
  parameters
• Babies lt3 are at greatest risk of morbidity and
  mortality.
• Babies who are constitutionally small are at less
  risk of complications than those who are SGA from
  pathologic process.

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Etiology of SGA

• Maternal Factors
• Placental Factors
• Fetal Factors

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Maternal Factors

• Genetic size
• Demographics
• Age (extremes of reproductive age)
• Race
• Socioeconomic status
• Underweight before pregnancy or malnutrition
• Chronic disease
• Exposure to teratogens (EtOH, drugs, radiation,
  etc.)

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Maternal Factors (cont.)
Factors that interfere with placental flow and
function

• Postmaturity
• Multiple gestation
• Uterine anomalies
• Thrombotic disease
• High altitude environment
• Smoking
• Cocaine

• Heart disease
• Renal disease
• Hypertension
• Pulmonary disease
• Hemoglobinopathies
• Collagen-vascular disease
• Diabetes

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Placental Factors

• Malformations vascular
• Chorioangioma
• Infarction
• Abruption
• Previa
• Abnormal trophoblast invasion

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Fetal Factors

• Constitutional genetically small, but
  genetically normal
• Chromosomal abnormality only about 5 of SGA
  babies
• Malformations CNS, skeletal, gastroschisis
• Congenital infections CMV, rubella

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Characteristics of IUGR

• Symmetric
• Early onset
• Constitutional or normal small
• Decreased growth potential
• Normal ponderal index
• Lower risk for transitional problems
• Brain symmetrical to body
• Examples
• Genetic causes, chromosomal
• TORCH infections
• Anomalad Syndromes

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Characteristics of IUGR

• Asymmetric
• Late onset
• Environmental
• Growth arrest
• Higher risk for transitional problems
• Brain sparing
• Examples
• Chronic hypoxia
• Preeclampsia (PIH, PET)
• Chronic hypertension
• Malnutrition

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Neonatal Complications of IUGR

• Mortality rate 5-20x that of AGA
• Perinatal asphyxia
• Abnormal temperature regulation
• Hypoglycemia
• Hyperviscosity-polycythemia syndrome
• Altered immunity
• Thrombocytopenia

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Neonatal Complications of IUGR(cont)

• Pulmonary hemorrhage
• PPHN
• Hypocalcemia

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Evaluation of SGA Newborn

• Careful physical examination
• Measure plot head circumference length
• CBC with differential and platelet count
• Monitor glucose carefully
• Further evaluation?
• Urine for CMV
• TORCH titers
• Liver function tests
• Head Ultrasound

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Long term Morbidity of IUGR

• Factors associated with abnormal outcome ?
• Microcephaly
• Hypoxic ischemic encephalopathy
• Symptomatic hypoglycemia
• Symptomatic hyperviscosity

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Growth Consequences of IUGR
Height at 4 years
Weight at 4 years
Percent
Percent
Percent
Percent
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Growth Consequences of IUGR
Head Circumference at 4 years
Percent
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Fetal Origins of Adult Diseases ?

• Coronary artery disease correlates inversely with
  birth weight
• Rate of non-insulin dependent diabetes mellitus
  is highest in the thinnest babies at birth (low
  ponderal index)
• High serum cholesterol are linked to
  disproportionate size at birth (body smaller than
  head)
• Increased rate of hypertension in infants who
  were thin, short, /or proportionately small at
  birth