Do I need to refer a patient with a history of Intrauterine Growth Restriction (IUGR) to Maternal-Fetal Medicine (MFM)?

Management of Patients with History of IUGR

Patients with a history of intrauterine growth restriction (IUGR) should be referred to Maternal-Fetal Medicine (MFM) specialists for subsequent pregnancies due to increased risk of recurrence and associated complications.

Rationale for MFM Referral

IUGR is associated with significant perinatal morbidity and mortality, requiring specialized surveillance and management in subsequent pregnancies. The Society for Maternal-Fetal Medicine (SMFM) guidelines provide clear recommendations for management of pregnancies with history of IUGR 1:

• Previous IUGR increases risk of recurrence in subsequent pregnancies
• Women with prior IUGR pregnancies have increased risk for hyperlipidemia, hypertriglyceridemia, and insulin resistance 1
• IUGR is associated with long-term cardiovascular risks for the mother 1
• MFM specialists have expertise in specialized ultrasound assessment and management of high-risk pregnancies 2

Surveillance Protocol for Subsequent Pregnancies

When managing a patient with history of IUGR in a subsequent pregnancy, the following surveillance protocol should be implemented:

Early Pregnancy Management

• Detailed obstetrical ultrasound examination, especially for patients with history of early-onset IUGR (<32 weeks) 3
• Consider low-dose aspirin for prevention of recurrent IUGR 3
• Baseline assessment of maternal medical conditions that may contribute to IUGR

Ongoing Surveillance

• Serial growth ultrasounds every 3-4 weeks starting at 24-28 weeks
• Weekly umbilical artery Doppler assessment if growth restriction is suspected 3
• Increase frequency of testing based on Doppler findings:
  • Normal umbilical artery Doppler: Weekly assessment
  • Decreased end-diastolic velocity: 2-3 times weekly
  • Absent/reversed end-diastolic velocity: More intensive monitoring (2-3 times weekly or daily) 1

Delivery Timing

Delivery timing should be based on umbilical artery Doppler findings if IUGR recurs 3:

• Normal umbilical artery Doppler with EFW between 3rd-10th percentile: 38-39 weeks
• Decreased diastolic flow: 37 weeks
• Absent end-diastolic velocity: 34 weeks
• Reversed end-diastolic velocity: 32 weeks

Common Pitfalls in IUGR Management

• Failure to distinguish between IUGR and constitutionally small fetuses: Not all small fetuses are pathologically growth restricted
• Inadequate surveillance: Weekly umbilical artery Doppler is the minimum standard for suspected IUGR
• Delayed referral: Early referral to MFM allows for timely implementation of preventive strategies
• Inconsistent terminology: Ensure clear communication using standardized definitions of IUGR (EFW <10th percentile) 4

Prevention of Recurrent IUGR

• Low-dose aspirin started in early pregnancy may prevent recurrent IUGR 3
• The American College of Obstetrics and Gynecology recommends low-dose aspirin in women with risk factors including history of IUGR 1
• Optimization of maternal medical conditions before conception
• Smoking cessation and nutritional counseling

MFM specialists provide valuable expertise in the management of these high-risk pregnancies, with access to specialized ultrasound assessment, interpretation of complex Doppler studies, and experience in timing delivery to optimize outcomes 2. Given the significant risks associated with recurrent IUGR and the specialized monitoring required, referral to MFM is strongly recommended for patients with history of IUGR in subsequent pregnancies.