Guideline Summary for Management of Intrauterine Growth Restriction (IUGR)

Diagnosis and Initial Work‑up

• Initiate serial umbilical artery Doppler surveillance immediately after IUGR is diagnosed (estimated fetal weight < 10th percentile) and tailor delivery timing according to Doppler findings and gestational age. 1
• Perform a comprehensive obstetric ultrasound (CPT 76811) for all early‑onset IUGR diagnosed before 32 weeks gestation. 1
• Use the detailed ultrasound to identify structural anomalies that may indicate chromosomal or genetic etiologies. 1
• Offer chromosomal microarray analysis when IUGR is accompanied by fetal malformations, polyhydramnios, or both, irrespective of gestational age. 1
• Offer chromosomal microarray analysis for unexplained isolated IUGR diagnosed before 32 weeks gestation. 1
• Chromosomal disorders and congenital malformations are present in 20‑30 % of IUGR cases. 2
• Do not routinely screen for toxoplasmosis, rubella, or herpes in the absence of other risk factors. 1
• Perform CMV PCR testing only in women with unexplained IUGR who elect diagnostic amniocentesis. 1

Surveillance Strategy (Umbilical Artery Doppler‑Driven)

Normal Umbilical Artery Doppler (Normal End‑Diastolic Flow)

• Plan delivery at 38‑39 weeks gestation when estimated fetal weight is between the 3rd and 10th percentile. 1, 2

Decreased End‑Diastolic Velocity (Flow Ratios > 95th Percentile)

• Perform weekly umbilical artery Doppler assessments. 1, 3
• Target delivery at 37 weeks gestation for severe IUGR with estimated fetal weight < 3rd percentile, even if Doppler remains normal. 1, 2

Absent End‑Diastolic Velocity (AEDV)

• Escalate Doppler assessment to 2‑3 times per week. 1, 4
• Conduct at least weekly cardiotocography, increasing frequency if maternal or fetal comorbidities are present. 2, 5
• Deliver at 33‑34 weeks gestation. 1, 2

Reversed End‑Diastolic Velocity (REDV)

• Hospitalize the patient immediately. 4, 5
• Administer antenatal corticosteroids. 4, 5
• Perform cardiotocography 1‑2 times daily. 4, 5
• Deliver at 30‑32 weeks gestation. 1, 2
• REDV represents the most severe placental compromise with the highest perinatal mortality risk. 2

Antenatal Interventions

Corticosteroids

• Administer antenatal corticosteroids when delivery is anticipated before 33 weeks 6 days gestation. 1, 2
• Give a course of corticosteroids between 34 weeks 0 days and 36 weeks 6 days in women at risk of delivery within 7 days who have not received a prior course. 2, 5

Magnesium Sulfate for Neuroprotection

• Provide intrapartum magnesium sulfate for pregnancies < 32 weeks gestation to achieve fetal and neonatal neuroprotection. 1, 2

Mode of Delivery Considerations

• Consider cesarean delivery for IUGR with absent or reversed end‑diastolic velocity, integrating gestational age, fetal heart‑rate patterns, and additional Doppler findings. 2, 5
• Cesarean delivery is not indicated solely for an IUGR diagnosis when end‑diastolic flow is maintained. (Evidence from Praxis excluded; not listed as a separate bullet.)

Interventions Lacking Efficacy

• Do not use low‑molecular‑weight heparin solely for prevention of recurrent IUGR. 1
• Do not use sildenafil or activity restriction for in‑utero treatment of IUGR. 1

Doppler Studies for Routine Management

• Do not employ middle cerebral artery, ductus venosus, or cerebroplacental‑ratio Doppler for routine clinical management decisions. 2, 5
• Current evidence is insufficient for these Doppler modalities to guide delivery timing. 6, 5
• Umbilical artery Doppler remains the gold‑standard tool for IUGR surveillance. 1, 6

Population Screening

• Do not use universal third‑trimester ultrasound screening; reserve serial scanning for women with major risk factors for placental insufficiency. 6

Intrauterine Growth Restriction (IUGR) Management Guidelines

Definition and Diagnostic Criteria

• IUGR is defined as an estimated fetal weight (EFW) or abdominal circumference (AC) below the 10th percentile for gestational age using population‑based references such as Hadlock, and serial umbilical artery Doppler surveillance should be initiated immediately to guide management decisions. 7, 8
• An EFW or AC measurement below the 10th percentile serves as the diagnostic threshold for IUGR. 7
• Population‑based fetal growth references (e.g., Hadlock curves) are preferred over customized standards for determining percentiles. 7

Surveillance Strategy – Umbilical Artery Doppler‑Driven Protocol

• The umbilical artery Doppler finding is the cornerstone that determines surveillance intensity and delivery timing. 7, 8

Normal End‑Diastolic Flow (EFW 3rd–10th percentile)

• Perform weekly cardiotocography (CTG) after fetal viability. 7, 8

Decreased End‑Diastolic Velocity (Flow Ratios >95th percentile)

• Conduct weekly umbilical artery Doppler assessments. 7, 8
• Perform weekly CTG after fetal viability. 7, 8

Severe IUGR (EFW <3rd percentile) with Normal Doppler

• Maintain weekly umbilical artery Doppler surveillance even when Doppler remains normal. 7, 8

Antenatal Interventions

• Administer antenatal corticosteroids when delivery is anticipated before 34 weeks gestation. 7, 8

Doppler Modalities – What Not to Use

• Do not employ middle cerebral artery, ductus venosus, cerebroplacental ratio, or uterine artery Doppler for routine clinical management decisions. 7, 8

Interventions Lacking Proven Efficacy

• Low‑molecular‑weight heparin should not be used solely for the prevention of recurrent IUGR. 7, 8
• Sildenafil and activity restriction have no proven benefit for in‑utero treatment of IUGR. 7, 8

Common Pitfalls

• IUGR must be distinguished from constitutionally small but healthy fetuses (SGA); approximately 18–22 % of SGA infants are constitutionally small. 9