Fetal Growth Restriction Management

Introduction to Fetal Growth Restriction

• The American College of Obstetricians and Gynecologists recommends against low-dose aspirin use solely for Fetal Growth Restriction (FGR) prevention due to conflicting evidence 1
• Low-molecular-weight heparin, sildenafil, and activity restriction are NOT recommended for prevention or in utero treatment of FGR (Grade 1B recommendation) 1

Ultrasound Screening and Diagnostic Testing

• Detailed anatomical survey ultrasound should be performed, especially with early-onset FGR (<32 weeks of gestation) 1
• First trimester ultrasound screening (11-14 weeks) and second trimester ultrasound with Doppler (20-24 weeks) are recommended 2
• Additional Doppler studies in the third trimester at monthly intervals: umbilical artery, uterine arteries, ductus venosus, and middle cerebral artery (particularly for early IUGR prior to 34 weeks) 2
• For late IUGR (diagnosed after 34 weeks), monitor abdominal circumference growth velocity and cerebroplacental ratio 2
• Consider prenatal diagnostic testing with chromosomal microarray (CMA) when unexplained isolated FGR was diagnosed at <32 weeks in previous pregnancy 1

Delivery Timing and Management

• Delivery timing should be based on umbilical artery Doppler findings and severity of growth restriction 1
• Normal umbilical artery Doppler and Estimated Fetal Weight (EFW) between 3rd-10th percentile: Deliver at 38-39 weeks gestation 1
• Absent end-diastolic velocity: Deliver at 33-34 weeks gestation 1
• Reversed end-diastolic velocity: Deliver at 30-32 weeks gestation 1
• Administer antenatal corticosteroids if delivery is anticipated before 33 6/7 weeks or between 34 0/7 and 36 6/7 weeks in women at risk of preterm delivery within 7 days 1
• Administer magnesium sulfate for fetal and neonatal neuroprotection for pregnancies <32 weeks gestation 1
• Consider cesarean delivery for pregnancies with absent/reversed end-diastolic velocity based on the clinical scenario 1

Maternal and Fetal Monitoring

• Monitor closely for development of hypertensive disorders, as maternal hypertension is common in early-onset FGR (present in 50% during pregnancy and 70% at delivery) 1
• Maternal hypertension is one of the most important independent determinants of poor outcomes and is associated with earlier delivery and lower birthweights 1
• The single most important prognostic factor in preterm fetuses with growth restriction is the gestational age at delivery, with a 1-2% increase in intact survival for every additional day spent in utero up until 32 weeks of gestation 1
• A standardized protocol for diagnosis and management appears to be associated with more favorable outcomes, as evidenced by the TRUFFLE study 1
• For patients with a history of intrauterine growth restriction (IUGR) in a previous pregnancy, increased surveillance with serial ultrasounds and umbilical artery Doppler assessments should be implemented in subsequent pregnancies to monitor for recurrence and improve perinatal outcomes, as recommended by the American College of Obstetricians and Gynecologists 1
• Chronic medical conditions, such as hypertension, diabetes, and autoimmune disorders, are additional risk factors to assess in patients with a history of IUGR, according to the American College of Cardiology 3
• Serial growth ultrasounds every 3-4 weeks starting at 24-28 weeks and weekly umbilical artery Doppler assessments should be performed if IUGR is suspected or diagnosed, as recommended by the American College of Obstetricians and Gynecologists 1, 4
• Increase surveillance based on Doppler findings, with normal umbilical artery Doppler requiring weekly assessment, decreased end-diastolic velocity or severe IUGR requiring weekly umbilical artery Doppler, absent end-diastolic velocity requiring Doppler assessment 2-3 times per week, and reversed end-diastolic velocity requiring hospitalization with daily cardiotocography monitoring, as recommended by the American College of Obstetricians and Gynecologists 1, 5