Intrauterine growth restriction (IUGR) or fetal growth restriction (FGR) is defined as an estimated fetal weight (EFW) and/or abdominal circumference (AC) at one point in time during pregnancy being below 3rd percentile or EFW and/or AC below the 10th percentile for gestational age with deranged Doppler parameters 14.
An IUGR can be broadly divided into two main types:
Some authors also enlist a third type termed: femur-sparing intrauterine growth restriction 10.
On this page:
Clinical assessment
The symphysis fundal height (SFH) can be a commonly used crude measurement.
Pathology
Etiology
IUGR can result from a vast number of causes:
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placental insufficiency (commonest cause overall)
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maternal conditions
maternal narcotics/smoking
maternal alcohol use: fetal alcohol syndrome
maternal diabetes: when severe maternal diabetes, there can be a paradoxical IUGR as opposed to fetal macrosomia
maternal malnutrition/starvation
maternal vascular conditions
certain medications
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other placental causes
increased incidence with a single umbilical artery
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fetal conditions
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triploidy (IUGR is of early-onset)
Down syndrome (not a dominant feature)
chromosome 4p deletion syndrome (Wolf-Hirschhorn syndrome)
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other syndromic anomalies
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in utero substance exposure
Radiographic features
Ultrasound
Sonographic parameters include:
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non-Doppler features
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reduced abdominal circumference (AC) and/or EFW
AC and/or EFW <3rd percentile
AC and/or EFW <10th percentile with deranged Doppler parameters
presence of oligohydramnios without ruptured membranes
increased head circumference (HC) to abdominal circumference (AC) ratio (in asymmetrical type)
advanced placental grade
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Doppler features (will require a chart to calculate absolute values)
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umbilical artery Doppler assessment
increased PI above 95th percentile
absent/reversed diastolic flow
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umbilical venous Doppler assessment
presence of pulsatility
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uterine arterial Doppler assessment
increased mean uterine artery PI above 95th percentile
presence of notching in mid to late pregnancy
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CP ratio
reduced below 5th percentile
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Treatment and prognosis
While there is no cure, management is reliant on a structured antenatal surveillance program with timely intervention in order to minimize fetal compromise.
Complications
There are many including:
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antepartum
stillbirth
iatrogenic prematurity
perinatal stroke
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intrapartum
abnormal fetal status (fetal heart rate tracing)
asphyxia
emergency Cesarean section
need for active neonatal resuscitation
perinatal stroke
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neonatal
hypothermia
hypoglycemia
hypocalcemia
polycythemia
sepsis
coagulopathy
hepatocellular dysfunction
intraventricular hemorrhage, especially in premature IUGR neonates <750 g
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pediatric
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increased risk of:
short stature
cerebral palsy
developmental delay
behavioral and emotional problems
lower IQ scores
chronic lung disease
future cardiovascular disease and hypertension
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Differential diagnosis
General considerations include:
incorrect dates