SGA/IUGRSGA/IUGR

Sue Ann Smith, MDSue Ann Smith, MDNeonatologistNeonatologist

Doernbecher Neonatal Care CenterDoernbecher Neonatal Care Center

Intrauterine Growth Restriction Intrauterine Growth Restriction (IUGR)(IUGR)

No universal definitionNo universal definition Any baby who does not achieve intrauterine Any baby who does not achieve intrauterine

growth potentialgrowth potential Usually defined as < 2 SD below the mean Usually defined as < 2 SD below the mean

for weight.for weight.

Small for Gestational Age (SGA)Small for Gestational Age (SGA)

Usually defined as <2SD or <10Usually defined as <2SD or <10 thth % for % for growth parameters growth parameters

Babies <3% are at greatest risk of morbidity Babies <3% are at greatest risk of morbidity and mortality.and mortality.

Babies who are constitutionally small are at Babies who are constitutionally small are at less risk of complications than those who less risk of complications than those who are SGA from pathologic process. are SGA from pathologic process.

Etiology of SGAEtiology of SGA

Maternal FactorsMaternal Factors Placental FactorsPlacental Factors Fetal FactorsFetal Factors

Maternal FactorsMaternal Factors

Genetic sizeGenetic size DemographicsDemographics

– Age (extremes of reproductive age)Age (extremes of reproductive age)– RaceRace– Socioeconomic statusSocioeconomic status

Underweight before pregnancy or malnutritionUnderweight before pregnancy or malnutrition Chronic diseaseChronic disease Exposure to teratogens (EtOH, drugs, radiation, Exposure to teratogens (EtOH, drugs, radiation,

etc.)etc.)

Maternal Factors (cont.)Maternal Factors (cont.)

Heart diseaseHeart disease Renal disease Renal disease HypertensionHypertension Pulmonary diseasePulmonary disease HemoglobinopathiesHemoglobinopathies Collagen-vascular Collagen-vascular

diseasedisease DiabetesDiabetes

PostmaturityPostmaturity Multiple gestationMultiple gestation Uterine anomaliesUterine anomalies Thrombotic diseaseThrombotic disease High altitude High altitude

environmentenvironment SmokingSmoking CocaineCocaine

Factors that interfere with placental flow and function

Placental FactorsPlacental Factors

Malformations – vascularMalformations – vascular ChorioangiomaChorioangioma InfarctionInfarction AbruptionAbruption PreviaPrevia Abnormal trophoblast invasionAbnormal trophoblast invasion

Fetal FactorsFetal Factors Constitutional – genetically small, but Constitutional – genetically small, but

genetically normalgenetically normal Chromosomal abnormality – only about 5% Chromosomal abnormality – only about 5%

of SGA babiesof SGA babies Malformations – CNS, skeletal, Malformations – CNS, skeletal,

gastroschisisgastroschisis Congenital infections – CMV, rubellaCongenital infections – CMV, rubella

Characteristics of IUGRSymmetricSymmetric Early onsetEarly onset Constitutional or “normal” smallConstitutional or “normal” small Decreased growth potentialDecreased growth potential Normal ponderal indexNormal ponderal index Lower risk for transitional Lower risk for transitional

problemsproblems Brain symmetrical to bodyBrain symmetrical to body

ExamplesExamples Genetic causes, chromosomal Genetic causes, chromosomal TORCH infectionsTORCH infections Anomalad SyndromesAnomalad Syndromes

Characteristics of IUGRCharacteristics of IUGRAsymmetricAsymmetric Late onsetLate onset EnvironmentalEnvironmental Growth arrestGrowth arrest Higher risk for transitional problemsHigher risk for transitional problems Brain sparingBrain sparing

ExamplesExamples Chronic hypoxiaChronic hypoxia Preeclampsia (PIH, PET)Preeclampsia (PIH, PET) Chronic hypertensionChronic hypertension MalnutritionMalnutrition

Neonatal Complications of Neonatal Complications of IUGRIUGR

Mortality rate 5-20x that of AGAMortality rate 5-20x that of AGA Perinatal asphyxia Perinatal asphyxia Abnormal temperature regulationAbnormal temperature regulation HypoglycemiaHypoglycemia Hyperviscosity-polycythemia syndromeHyperviscosity-polycythemia syndrome Altered immunityAltered immunity ThrombocytopeniaThrombocytopenia

Neonatal Complications of Neonatal Complications of IUGR(cont)IUGR(cont)

Pulmonary hemorrhagePulmonary hemorrhage PPHNPPHN HypocalcemiaHypocalcemia

Evaluation of SGA NewbornEvaluation of SGA Newborn

Careful physical examinationCareful physical examination Measure & plot head circumference & Measure & plot head circumference &

lengthlength CBC with differential and platelet countCBC with differential and platelet count Monitor glucose carefullyMonitor glucose carefully Further evaluation?Further evaluation?

– Urine for CMVUrine for CMV– TORCH titersTORCH titers– Liver function testsLiver function tests– Head UltrasoundHead Ultrasound

““Long term” Morbidity of Long term” Morbidity of IUGRIUGR

Factors associated with abnormal outcome ?Factors associated with abnormal outcome ? MicrocephalyMicrocephaly Hypoxic ischemic encephalopathyHypoxic ischemic encephalopathy Symptomatic hypoglycemiaSymptomatic hypoglycemia Symptomatic hyperviscositySymptomatic hyperviscosity

Growth Consequences of IUGR

50

40

20

30

10

>9050-9010-50<10

Height at 4 years

50

40

20

30

10

>9050-9010-50<10

Weight at 4 years

Percent Percent

Perc

ent

Perc

ent

Term AGA Term SGA Preterm SGA

Growth Consequences of IUGR

50

40

20

30

10

>9050-9010-50<10

Head Circumference at 4 years

Percent

Term AGA Term SGA Preterm SGA

Fetal Origins of Adult Fetal Origins of Adult Diseases ?Diseases ?

Coronary artery disease correlates inversely Coronary artery disease correlates inversely with birth weightwith birth weight

Rate of non-insulin dependent diabetes Rate of non-insulin dependent diabetes mellitus is highest in the “thinnest” babies mellitus is highest in the “thinnest” babies at birth (low ponderal index)at birth (low ponderal index)

High serum cholesterol are linked to High serum cholesterol are linked to disproportionate size at birth (body smaller disproportionate size at birth (body smaller than head)than head)

Increased rate of hypertension in infants Increased rate of hypertension in infants who were thin, short, &/or proportionately who were thin, short, &/or proportionately small at birthsmall at birth