What are the management guidelines for Intrauterine Growth Restriction (IUGR) based on Royal College of Obstetricians and Gynaecologists (RCOG) and National Health Service (NHS) National Institute for Health and Care Excellence (NICE) recommendations?

Management of Intrauterine Growth Restriction (IUGR) Based on RCOG and NICE Guidelines

Umbilical artery Doppler assessment should be the cornerstone of surveillance for IUGR fetuses, with timing of delivery based on Doppler findings and gestational age to reduce perinatal mortality and morbidity. 1, 2

Diagnosis and Classification

• IUGR is defined as an ultrasonographic estimated fetal weight (EFW) or abdominal circumference (AC) below the 10th percentile for gestational age 2
• Classification:
  • Early-onset IUGR: diagnosed <32 weeks gestation 1
  • Late-onset IUGR: diagnosed ≥32 weeks gestation 1
  • Severe IUGR: EFW <3rd percentile 1, 2

Initial Assessment

• Detailed obstetrical ultrasound examination should be performed when IUGR is identified, as up to 20% of cases are associated with fetal or chromosomal abnormalities 2
• Prenatal diagnostic testing with chromosomal microarray analysis (CMA) should be offered when unexplained isolated IUGR is diagnosed at <32 weeks 1, 2
• At first diagnosis of IUGR, assessment should include fetal biometry, amniotic fluid volume, and umbilical artery Doppler waveform analysis 1

Surveillance Protocol

For EFW 3rd-9th percentile:

• Umbilical artery Doppler every 1-2 weeks initially; if stable, can extend to every 2-4 weeks 1
• Cardiotocography (CTG) once per week 1
• Consider EFW assessment every 2 weeks 1
• Fetal growth evaluation no more frequently than every 2 weeks 1

For EFW <3rd percentile (Severe IUGR):

• Weekly umbilical artery Doppler assessment 1
• Weekly cardiotocography 1
• Consider EFW assessment every 2 weeks 1

For Abnormal Umbilical Artery Doppler:

• With decreased end-diastolic velocity (elevated PI/RI/S:D ratio >95th percentile): weekly umbilical artery Doppler evaluation 1
• With absent end-diastolic velocity (AEDV): Doppler assessment 2-3 times per week 1
• With reversed end-diastolic velocity (REDV): hospitalization, daily CTG monitoring, and consideration of delivery 1

Timing of Delivery Based on Doppler Findings

• Normal umbilical artery Doppler: Consider delivery at 38-39 weeks 1, 2
• Elevated umbilical artery indices (decreased diastolic flow): Consider delivery at >37 weeks 1, 2
• Absent end-diastolic flow: Consider delivery at >34 weeks if surveillance remains reassuring 1
• Reversed end-diastolic flow: Consider delivery at >32 weeks if surveillance remains reassuring 1
• Severe IUGR (EFW <3rd percentile): Recommend delivery at 37 weeks 2

Antenatal Interventions

• Antenatal corticosteroids should be administered between 24+0 and 34+0 weeks gestation, but may be given up until 38+0 weeks in cases of elective cesarean delivery 1
• Antenatal corticosteroids should be administered if absent or reversed end-diastolic flow is noted at <34 weeks 1, 2
• Close observation for 48-72 hours after corticosteroid administration is recommended, as there may be transient return of end-diastolic flow in about two-thirds of cases 1, 2
• Magnesium sulfate for fetal neuroprotection should be administered in gestations before 32 weeks 1, 2

Mode of Delivery

• For pregnancies with IUGR complicated by absent or reversed end-diastolic velocity, cesarean delivery should be considered based on the clinical scenario 2
• Daily cardiotocograph monitoring is recommended with absent end-diastolic flow before 34 weeks 1
• With reversed end-diastolic flow before 30 weeks, hospital admission with daily cardiotocograph monitoring is recommended 1

Special Considerations

• Women with early-onset IUGR should be closely monitored for development of hypertensive disorders, as maternal hypertension is present in up to 70% of these cases at delivery 2
• The single most important prognostic factor in preterm fetuses with growth restriction is the gestational age at delivery, with an increase of 1%-2% in intact survival for every additional day in utero up until 32 weeks 2
• Doppler of any vessel is not recommended as a screening tool for identification of pregnancies that will subsequently be complicated by IUGR 1

Common Pitfalls and Caveats

• Do not confuse IUGR with small for gestational age (SGA), which is simply a statistical definition without implying pathology 3
• Avoid relying solely on estimated fetal weight for management decisions; incorporate Doppler findings which better reflect fetal compromise 4
• Remember that IUGR fetuses are at higher risk of intrapartum compromise and may quickly decompensate once uterine contractions have started 5
• Be aware that the optimal timing of delivery requires balancing the risks of prematurity against the risks of continued intrauterine compromise 6, 5