What is the management for a fetus with intrauterine growth restriction (IUGR)?

Management of Intrauterine Growth Restriction (IUGR)

Umbilical artery Doppler assessment should be the cornerstone of surveillance for fetuses with suspected IUGR, as its use is associated with significant decrease in perinatal mortality. 1

Diagnosis and Definition

• IUGR is defined as estimated fetal weight (EFW) below the 10th percentile for gestational age, with severe IUGR defined as EFW below the 3rd percentile 2
• When IUGR is suspected, perform a detailed obstetrical ultrasound to rule out fetal or chromosomal abnormalities, especially for early-onset IUGR (<32 weeks) 2

Surveillance Protocol

Doppler Assessment

• Normal umbilical artery Doppler:

  • Weekly umbilical artery Doppler assessment 1, 2
  • Consider delivery at 38-39 weeks 1, 2

• Abnormal umbilical artery Doppler:

  • Decreased diastolic flow: Increase frequency of testing; consider delivery at >37 weeks 1, 2
  • Absent end-diastolic flow (AEDV): Doppler assessment 2-3 times per week; consider delivery at >34 weeks 1, 2
  • Reversed end-diastolic flow (REDV): Hospitalization with daily monitoring; consider delivery at >32 weeks 1, 2

Additional Monitoring

• Twice weekly nonstress testing with weekly amniotic fluid evaluation, or weekly biophysical profile testing 1
• For absent or reversed end-diastolic flow, nonstress tests and/or biophysical profiles should be performed twice weekly or more often 1
• Consider hospitalization when fetal testing more than 3 times per week is necessary 1

Antenatal Corticosteroids

• Administer antenatal corticosteroids if absent or reversed end-diastolic flow is noted at <34 weeks (Level I evidence, level A recommendation) 1
• Close observation for 48-72 hours after corticosteroid administration is recommended due to potential transient increased physiologic and metabolic demands 1, 2
• Corticosteroid administration may result in transient return of end-diastolic flow in about two-thirds of cases 1

Timing of Delivery

The timing of delivery should balance the risks of prematurity against those of continued intrauterine existence 3:

• Normal umbilical artery Doppler with EFW 3rd-10th percentile: Deliver at 38-39 weeks 1, 2
• Decreased diastolic flow OR severe IUGR (EFW <3rd percentile): Deliver at 37 weeks 2
• Absent end-diastolic velocity (AEDV): Deliver at 34 weeks if fetal surveillance remains reassuring 1, 2
• Reversed end-diastolic velocity (REDV): Deliver at 32 weeks if fetal surveillance remains reassuring 1, 2

Special Considerations

• Early-onset IUGR (<32 weeks) is more likely associated with placental insufficiency and abnormal Doppler findings, requiring more intensive surveillance 2
• For very early gestational age IUGR with absent or reversed end-diastolic flow (e.g., at 25 weeks), aggressive interventions may be deferred given the poor prognosis for survival 1
• Magnesium sulfate is recommended for fetal and neonatal neuroprotection for pregnancies <32 weeks gestation 2
• Consider cesarean delivery for pregnancies with AEDV/REDV based on the clinical scenario 2

Management Algorithm

1. Confirm IUGR diagnosis with detailed ultrasound
2. Exclude infections and anomalies
3. Initiate umbilical artery Doppler assessment
4. Determine surveillance frequency based on Doppler findings
5. Administer corticosteroids if delivery anticipated <34 weeks
6. Time delivery according to Doppler findings and gestational age
7. Consider magnesium sulfate for neuroprotection if <32 weeks

This approach aims to achieve delivery of the newborn in the best possible condition, balancing the risks of prematurity against those of continued intrauterine existence 3.