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Intrauterine Growth RestrictionIUGR
Dana Rivera, M.D.
October, 2010
SGA vs IUGR
SGA: BW less than population
norms
< 10th %-tile OR
< 2 standard deviations below the mean (~3rd %-tile)
pathologic or non-pathologic causes
IUGR: BW < expected
inhibition of normal growth potential
implies pathology
True or False?
All SGA infants are IUGRFalse
All IUGR infants are SGAFalse
Normal Intrauterine Growth
Stage 1 Stage 2 Stage 3
Hyperplasia Hyperplasia/ hypertrophy Hypertrophy
4-20 weeks 20-28 weeks 28-40 weeks
Rapid mitosis Declining mitosis Rapid hypertrophy
Increasing DNA content Increasing cell size Rapid increasing cell size
rapid accumulation of fat, muscle, connective tissue
Symmetric Mixed- asymmetric Asymmetric
Symmetric
- Stage I growth inhibitionFewer cells but
normal size
- weight, head, length all < 10th percentile
Perinatal problems?
Higher
Lower
Growth potential?
Higher
Lower
Asymmetric
- Stage II/III growth inhibitionDecrease in cell
size, less effect on total cell number
- weight below 10th percentile,head and length preserved
Perinatal problems?
Higher
Lower
Growth potential?
Higher
Lower
What factors affect fetal weight?
Sexterm males 150 gm
heavier and 0.9 cm longer than females
Parity1st born infants smaller
effect loss after 3rd birth
Race, ethnicity, nationality
AltitudeDenver population growth
curves under estimate weights of infants born at sea level
Maternal sizematernal pre-pregnancy
weight and pregnancy weight gain correlate with fetus size
“Maternal constraint”- non-genetic
Number of fetusesReduced rate of fetal
growth of multiples
Small breed embryo transplanted into large breed uterus will grow larger
Hormonal Factors
Insulin Major hormone for in
utero growth
Produced by fetus
Promotes fetal adipose deposition, glycogen stores
Etiology- Overlapping
Maternal factorsMedical disease (US) Malnutrition (world-
wide)Multiple pregnancyDrugsHypoxemia
Small stature/ low pre-pregnancy weight
Teen pregnancyLow SESPrima gravidaGrand multiparity
Maternal, Fetal, Placenta
Fetal
GeneticCongenital malformationsGenetic/ chromosomal (trisomies, syndromes)Cardiovascular diseaseCongenital infection Inborn errors of metabolism
Placenta
placental insufficiencypost dates
anatomicabnormal insertionhemangiomasinfarctsabruption
Case # 1
A baby is delivered at 36 WGA via repeat C- sectionBW- 2 kgHC- < 10th %tileLt- < 10th %tile
CMV
Case #1- What if?
Toxoplasmosis
Rubella
“TORCH” Stigmata
hepatoslpenomegalypetechiae/ ecchymosesblueberry muffin rashvesicles/ mucocutaneous lesionschorioretinitis/ cataracts/ salt-pepper retinopathyPPS/PDAmicrocephaly/ hydrocephaly
Intracranial calcifications
Diagnosis Algorithm
IUGR
yesTORCH stigmata work-up? no
Case # 2
A baby is delivered via NSVD, no prenatal care, EGA 35 weeksBW- 1500 gmHC- < 10thLt- <10th
Trisomy 13
Case #2- What if?
Trisomy 18 Turner syndrome
Diagnosis Algorithm
IUGR
yesTORCH stigmata work-up? no yesDysmorphic features work-up? no
Case # 3
Infant is delivered at 38 weeks to mom who presents with headaches and epigastric painBW: 2.1 kgHC: 50th%tileLt: 30th%tile
Pre-eclampsia/ HELLP
Case # 3- What if?
Mom with no prenatal care delivers undiagnosed twins at EGA 34 weeks
Discordant twins
Case # 3- What if?
An infant is delivered at 42 weeks via c- section due to NRHTs after induction
Post dates - decreased subcutaneous fat- skin desquamation- wizened facies - large AF(diminished membranous bone formation)- meconium staining
Diagnosis Algorithm
IUGR
yesTORCH stigmata work-up? no yesDysmorphic features work-up? no
yesMaternal/placental explanation work-up?
no
Case # 3- What if?
Infant delivered at EGA 34 weeks to mom with no prenatal care and positive tox screen
Diagnosis Algorithm
IUGR
yesTORCH stigmata work-up? no yesDysmorphic features work-up? no
yesMaternal/placental explanation work-up?
no yes
Maternal drug use tox screenno
Unknown cause
True or False
IUGR infants are prone to asphyxia
True
Why or why not?Perinatal hypoxia
Chronic and acute Increased C/S rate,
decreased Apgar, increased resuscitation need
An IUGR infant is at risk for
Hypothermia?
Hypoglycemia?
Or
Hypocalcemia?
decreased subcutaneous fat, increased surface- volume ratio, decreased heat production
decreased glycogen stores/ glycogenolysis/ gluconeogenesis
increased metabolic rate
deficient catecholamine release
Associated with perinatal stress, asphyxia, prematurity
Which lab result(s) would not be associated with IUGR?WBC 4, S8 & B1H & H 11/ 33Plt 65PT 16PTT 56Direct bilirubin 4.5
NeutropeniaPolycythemia
Elevated erythropoietin
Thrombocytopenia Elevated coagsTORCH
Which CxR is more consistent with IUGR?
Increased meconium aspiration
Decreased surfactant deficiency
Perinatal problems
Perinatal asphyxiaHypothermiaHypoglycemiaHypocalcemiaPolycythemia,
hyperviscosityThrombocytopenia
NeutropeniaElevated coagsDecreased surfactant
deficiencyIncreased meconium
aspiration syndromeDirect
hyperbilirubinemia
Evaluation and Management
Physical examLabs
- blood sugar - urine shell vial (CMV)
- calcium - viral cultures (HSV)
- CBC diff/plt - syphilis w/u
- bilirubin - tox screen
- head ultrasound - chromosomes
- total IgM vs specific
Quick algorithm
Evaluation and Management
Monitor postnatal weight gain/ head growthneeds may exceed
100-120 cal/kg/dcatch- up by 6-12
monthsHypersomatotropism-
accelerated growth velocity
? Safety of aggressive feeding
rapid weight gain may predispose to childhood obesity highest risk for developing type 2 DM
IUGR- Outcome
Neurodevelopmentetiology and adverse event dependentlower intelligence, learning/ behavioral
disorders, neurologic handicapssymmetric, chromosomal disorders, congenital
infections--- poorer outcomeschool performance influenced by social class
World’s smallest…..