Management of Intrauterine Growth Restriction (IUGR)

Introduction to IUGR Management

• The American College of Obstetricians and Gynecologists recommends a structured approach with umbilical artery Doppler assessment as the cornerstone of surveillance, followed by timely delivery based on Doppler findings and gestational age to reduce perinatal mortality and morbidity 1, 2

Diagnosis and Initial Assessment

• IUGR is defined as an ultrasonographic estimated fetal weight or abdominal circumference below the 10th percentile for gestational age, according to the American College of Obstetricians and Gynecologists 3
• Population-based fetal growth references should be used to determine fetal weight percentiles, as recommended by the American College of Obstetricians and Gynecologists 3
• When early-onset IUGR is identified, a detailed obstetrical ultrasound examination should be performed, as up to 20% of cases are associated with fetal or chromosomal abnormalities, according to the American College of Obstetricians and Gynecologists 4
• Diagnostic testing with chromosomal microarray analysis should be offered when IUGR is detected with fetal malformation or polyhydramnios, or when unexplained isolated IUGR is diagnosed at less than 32 weeks, as recommended by the American College of Obstetricians and Gynecologists 4

Surveillance Protocol

• Antepartum surveillance of a viable fetus with suspected IUGR should include Doppler of the umbilical artery, as its use is associated with a significant decrease in perinatal mortality, with a Level A recommendation from the American College of Obstetricians and Gynecologists 5, 2
• Weekly umbilical artery Doppler assessment should be performed in conjunction with other antepartum testing, as recommended by the American College of Obstetricians and Gynecologists 2
• Weekly cardiotocography testing after viability is recommended for IUGR without absent or reversed end-diastolic velocity, according to the American College of Obstetricians and Gynecologists 1
• Frequency of testing should be increased when IUGR is complicated by absent or reversed end-diastolic velocity or other comorbidities, as recommended by the American College of Obstetricians and Gynecologists 1, 2

Timing of Delivery Based on Doppler Findings

• Consider delivery at 38-39 weeks of gestation when estimated fetal weight is between the 3rd and 10th percentile, as recommended by the American College of Obstetricians and Gynecologists 1, 2
• Recommend delivery at 37 weeks of gestation or for severe IUGR with estimated fetal weight less than the 3rd percentile, according to the American College of Obstetricians and Gynecologists 1, 2
• Recommend delivery at 33-34 weeks of gestation for absent end-diastolic flow, as long as fetal surveillance remains reassuring, as recommended by the American College of Obstetricians and Gynecologists 1, 6
• Recommend delivery at 30-32 weeks of gestation for reversed end-diastolic flow, as long as fetal surveillance remains reassuring, according to the American College of Obstetricians and Gynecologists 1, 6

Antenatal Interventions

• Antenatal corticosteroids should be administered if absent or reversed end-diastolic flow is noted at less than 34 weeks, with a Level A recommendation from the American College of Obstetricians and Gynecologists 5, 1
• Close observation for 48-72 hours after corticosteroid administration is reasonable, as there may be transient return of end-diastolic flow in about two-thirds of cases, according to the American College of Obstetricians and Gynecologists 5
• Intrapartum magnesium sulfate for fetal and neonatal neuroprotection is recommended for women with pregnancies less than 32 weeks of gestation, as recommended by the American College of Obstetricians and Gynecologists 1

Mode of Delivery

• For pregnancies with IUGR complicated by absent or reversed end-diastolic velocity, cesarean delivery should be considered based on the entire clinical scenario, according to the American College of Obstetricians and Gynecologists 1

Special Considerations

• Women with early-onset IUGR should be closely monitored for the development of hypertensive disorders of pregnancy, as maternal hypertension is present in up to 70% of these cases at delivery, as recommended by the American College of Obstetricians and Gynecologists 3
• 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 spent in utero up until 32 weeks of gestation, according to the American College of Obstetricians and Gynecologists 3

Medications for Intrauterine Growth Restriction Management

Introduction to IUGR Management

• The American College of Obstetricians and Gynecologists states that no preventative strategies or treatments for fetal growth restriction have been proven effective, and management relies on surveillance and timely delivery, not drug therapy 7

Ineffective and Contraindicated Treatments

• Low-molecular-weight heparin should not be used for prevention of recurrent IUGR, with a GRADE 1B recommendation from the American College of Obstetricians and Gynecologists 7
• Sildenafil should not be used for in utero treatment of IUGR, with a GRADE 1B recommendation from the American College of Obstetricians and Gynecologists 7
• Activity restriction/bed rest should not be used for treatment of IUGR, with a GRADE 1B recommendation from the American College of Obstetricians and Gynecologists 7
• Nutritional and dietary supplements have no consistent evidence for preventing IUGR or reducing small-for-gestational-age births, according to the American College of Obstetricians and Gynecologists 7

Aspirin for Prevention

• Low-dose aspirin should NOT be used solely for IUGR prevention in otherwise low-risk women, according to the American College of Obstetricians and Gynecologists 7

Medications for Perinatal Support

• Antenatal corticosteroids should be administered if delivery is anticipated before 33 6/7 weeks or between 34 0/7 and 36 6/7 weeks in women at risk of delivery within 7 days who haven't received prior course, with a GRADE 1A recommendation from the American College of Obstetricians and Gynecologists 8
• Intrapartum magnesium sulfate should be administered for pregnancies <32 weeks gestation for fetal and neonatal neuroprotection, with a GRADE 1A recommendation from the American College of Obstetricians and Gynecologists 8

Management Focus

• Delivery should be considered at 37 weeks with decreased diastolic flow or severe IUGR (<3rd percentile), according to the American College of Obstetricians and Gynecologists 8
• Delivery should be considered at 33-34 weeks with absent end-diastolic velocity, according to the American College of Obstetricians and Gynecologists 8
• Delivery should be considered at 30-32 weeks with reversed end-diastolic velocity, according to the American College of Obstetricians and Gynecologists 8

Management of Intrauterine Growth Restriction with Anhydramnios in Gestational Diabetes

Delivery Timing Based on Umbilical Artery Doppler

• When umbilical artery Doppler shows normal or decreased diastolic flow, schedule delivery at 37 weeks (or immediately if already beyond 37 weeks). This follows the American College of Obstetricians and Gynecologists (ACOG) recommendation that IUGR with oligohydramnios/anhydramnios be delivered between 34–37 weeks. 9

• If absent end‑diastolic velocity (AEDV) is present, plan delivery at 33–34 weeks provided fetal surveillance remains reassuring; anhydramnios may require delivery sooner regardless of gestational age. 10

• If reversed end‑diastolic velocity (REDV) is present, plan delivery at 30–32 weeks provided fetal surveillance remains reassuring; anhydramnios often mandates immediate delivery irrespective of gestational age. 10

Critical Pre‑Delivery Interventions

• Administer antenatal corticosteroids promptly when gestational age is <34 weeks to enhance fetal lung maturity, and monitor the fetus for 48–72 hours after administration. 10

• Perform a detailed umbilical artery Doppler assessment before deciding on delivery mode; absent or reversed end‑diastolic velocity markedly increases the likelihood that cesarean delivery will be required. 10

Fetal Surveillance Until Delivery

• Conduct daily cardiotocography (CTG); the appearance of spontaneous repetitive late decelerations should trigger immediate delivery regardless of Doppler findings. 9

• Increase the frequency of umbilical artery Doppler studies to at least twice weekly (or more) because anhydramnios heightens the risk of rapid deterioration. 9

• Do not rely on the biophysical profile (BPP) as the primary surveillance tool, since oligohydramnios/anhydramnios automatically yields an abnormal BPP and the test has high false‑positive and false‑negative rates in IUGR. 9

Delivery Planning and Pitfalls

• Avoid delaying delivery to achieve tighter glycemic control; the combination of IUGR and anhydramnios reflects severe placental insufficiency with a high stillbirth risk. 9

• Do not extend expectant management beyond 37 weeks even if testing appears reassuring; ACOG advises delivery by 34–37 weeks for IUGR with oligohydramnios/anhydramnios. 9

• Recognize that amniotic fluid abnormalities alone do not independently worsen outcomes in IUGR (as shown in the PORTO study), but anhydramnios represents a more severe end of the spectrum and should be managed accordingly. 9