How should patients with a history of Intrauterine Growth Restriction (IUGR) be managed in a subsequent pregnancy?

Management of Patients with History of IUGR in Subsequent Pregnancies

Patients with a history of intrauterine growth restriction (IUGR) in a previous pregnancy should receive increased surveillance with serial ultrasounds and umbilical artery Doppler assessments in subsequent pregnancies to monitor for recurrence and improve perinatal outcomes. 1

Risk Assessment and Preventive Measures

Initial Evaluation

• Conduct thorough assessment of risk factors for recurrent IUGR:
  • Chronic medical conditions (hypertension, diabetes, autoimmune disorders) 1
  • Previous pregnancy complications (preeclampsia, placental insufficiency)
  • Lifestyle factors (smoking, substance use)

Preventive Interventions

• Low-dose aspirin is NOT recommended for the sole indication of preventing recurrent FGR in otherwise low-risk women 2
• The American College of Obstetricians and Gynecologists recommends against low-dose aspirin use solely for FGR prevention due to conflicting evidence 2
• Low-molecular-weight heparin is NOT recommended for prevention of recurrent FGR (Grade 1B recommendation) 2
• Sildenafil and activity restriction are NOT recommended for in utero treatment of FGR (Grade 1B recommendation) 2

Surveillance Protocol

Early Pregnancy (First and Second Trimester)

• Detailed anatomical survey ultrasound (CPT code 76811) should be performed, especially with early-onset FGR (<32 weeks of gestation) 2, 1
• Consider prenatal diagnostic testing with chromosomal microarray (CMA) when unexplained isolated FGR was diagnosed at <32 weeks in previous pregnancy 2
• First trimester ultrasound screening (11-14 weeks) 2
• Second trimester ultrasound with Doppler, preferably at 20-24 weeks 2

Third Trimester Monitoring

• Implement serial growth ultrasounds every 3-4 weeks starting at 24-28 weeks 1

• Umbilical artery Doppler assessments should be performed if IUGR is suspected or diagnosed 1

• Frequency of monitoring based on Doppler findings:

  1. Normal umbilical artery Doppler: Weekly assessment
  2. Decreased end-diastolic velocity or severe IUGR: Weekly umbilical artery Doppler
  3. Absent end-diastolic velocity: Doppler assessment 2-3 times per week
  4. Reversed end-diastolic velocity: Hospitalization with daily cardiotocography monitoring 1

• 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

Timing of Delivery

Delivery timing should be based on umbilical artery Doppler findings and severity of growth restriction:

1. Normal umbilical artery Doppler and EFW between 3rd-10th percentile: Deliver at 38-39 weeks gestation 2, 1
2. Decreased diastolic flow or severe IUGR (EFW <3rd percentile): Deliver at 37 weeks gestation 1
3. Absent end-diastolic velocity: Deliver at 33-34 weeks gestation 2, 1
4. Reversed end-diastolic velocity: Deliver at 30-32 weeks gestation 2, 1

Peripartum Management

Antenatal Interventions

• 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 2, 1
• Administer magnesium sulfate for fetal and neonatal neuroprotection for pregnancies <32 weeks gestation 2, 1

Mode of Delivery

• Consider cesarean delivery for pregnancies with absent/reversed end-diastolic velocity based on the clinical scenario 2, 1
• Close observation for 48-72 hours after corticosteroid administration due to potential transient increased physiologic and metabolic demands 1

Monitoring for Complications

• 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 in the TRUFFLE study) 2
• Maternal hypertension is one of the most important independent determinants of poor outcomes and is associated with earlier delivery and lower birthweights 2

Important Caveats

• FGR and SGA are distinct conditions with different implications; FGR is associated with greater perinatal morbidity, prematurity, mortality, and increased risk for diseases in later life 3
• 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 2
• A standardized protocol for diagnosis and management appears to be associated with more favorable outcomes, as evidenced by the TRUFFLE study 2