What is the significance of fetal growth restriction (FGR) in labor and delivery?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: March 6, 2026 • View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Significance of Fetal Growth Restriction in Labor and Delivery

Fetal growth restriction (FGR) is a leading cause of perinatal morbidity and mortality, occurring in up to 10% of pregnancies, with stillbirth rates approximately twice that of normally grown fetuses and significantly increased risks of intrapartum complications including fetal heart rate decelerations, emergency cesarean delivery, and metabolic acidemia. 1

Critical Perinatal Risks

Mortality and Morbidity Impact

  • Stillbirth risk is approximately 1.5% for fetuses below the 10th percentile, increasing to 2.5% for those below the 5th percentile 1
  • Infants with birthweights below the 10th percentile face significantly higher rates of severe acidosis at birth, low 5-minute Apgar scores, and NICU admissions 1
  • Preterm FGR fetuses have a 2- to 5-fold increased rate of perinatal death compared with term FGR fetuses 1
  • The worst outcomes occur in fetuses with estimated fetal weights (EFW) less than the 3rd percentile or those with fetal Doppler abnormalities 1

Intrapartum Complications

  • Growth-restricted fetuses, particularly those with absent or reversed end-diastolic velocity (AEDV/REDV), face 75-95% rates of intrapartum fetal heart rate decelerations requiring cesarean delivery in older studies 1
  • Labor represents a particularly stressful event for FGR fetuses due to uterine contractions causing up to 60% reduction in uteroplacental perfusion 2
  • FGR fetuses are at increased risk for metabolic acidemia at delivery, especially those with abnormal umbilical artery Doppler 1

Evidence-Based Delivery Timing

Severe FGR or Abnormal Doppler

The Society for Maternal-Fetal Medicine provides clear gestational age thresholds based on Doppler findings:

  • Deliver at 37 weeks for FGR with decreased diastolic flow (S/D, RI, or PI >95th percentile) without AEDV/REDV, or for severe FGR with EFW <3rd percentile (GRADE 1B) 1
  • Deliver at 33-34 weeks for FGR with absent end-diastolic velocity (AEDV) (GRADE 1B) 1
  • Deliver at 30-32 weeks for FGR with reversed end-diastolic velocity (REDV) (GRADE 1B) 1

Mild FGR with Normal Doppler

  • Deliver at 38-39 weeks when EFW is between 3rd and 10th percentile with normal umbilical artery Doppler (GRADE 2C) 1

Periviable Period Considerations

  • For severe early-onset FGR at 24-26 weeks, survival rates are extremely poor: 0% intact survival at 24 weeks, 13% at 25 weeks, and 6-31% at 26 weeks 1
  • Thresholds of 26 weeks gestation or 500g have been suggested for delivery decisions, requiring coordination between maternal-fetal medicine and neonatology with comprehensive counseling 1

Mode of Delivery Considerations

Cesarean Delivery Indications

  • For pregnancies with FGR complicated by AEDV/REDV, cesarean delivery should be considered based on the entire clinical scenario (GRADE 2C) 1
  • National guidelines from 4 countries recommend cesarean delivery when FGR is complicated by AEDV/REDV of the umbilical artery 1
  • Risk factors for cesarean during trial of labor include oligohydramnios (OR 3.98) and prostaglandin use for cervical ripening (OR 3.67) 3

Trial of Labor Feasibility

  • Despite historical concerns, recent data shows 84% vaginal delivery rate for FGR undergoing trial of labor, with 83% success even among induced patients 3
  • After reaching active phase of labor, cesarean delivery risk is very low (3.1%) with short duration (173±145 minutes) 4
  • Factors associated with increased cesarean risk during induction with unfavorable cervix include maternal age >39 years (OR 4.33), nulliparity (OR 3.49), and abnormal umbilical artery Doppler (OR 3.50) 5

Essential Intrapartum Management

Fetal Monitoring

  • Continuous cardiotocography (CTG) is recommended during labor for FGR due to increased risk of intrapartum hypoxia 2
  • Weekly CTG testing after viability for FGR without AEDV/REDV, with increased frequency when complicated by AEDV/REDV or other comorbidities (GRADE 2C) 1

Neuroprotection and Corticosteroids

  • Administer antenatal corticosteroids if delivery 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 (GRADE 1A) 1
  • Administer intrapartum magnesium sulfate for fetal neuroprotection when <32 weeks gestation (GRADE 1A) 1

Long-Term Implications

  • FGR is associated with metabolic programming that increases risk of future metabolic syndrome, cardiovascular disease, and endocrine diseases 1
  • Identified early-onset FGR has increased risk of severe childhood outcomes (OR 3.00) compared to non-identified SGA 6

Critical Pitfalls to Avoid

  • Do not delay delivery beyond recommended gestational ages based on Doppler findings, as neonatal morbidity/mortality from FGR exceeds prematurity risks at specified thresholds 1
  • Do not assume all FGR requires cesarean delivery; trial of labor is reasonable for most cases without AEDV/REDV 3
  • Do not use biophysical profile as the only form of surveillance; umbilical artery Doppler is essential 1
  • Recognize that rapid labor progression and high incidence of uterine tachysystole may occur after active phase in induced FGR pregnancies 4

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

3
Research

Fetal growth restriction: risk factors for unplanned primary cesarean delivery.

The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, 2015

Related Questions

What is the recommended intrapartum fetal surveillance for a multi-gravida (woman who has been pregnant more than once) at 38 weeks with induction of labor due to intrauterine growth restriction (IUGR) and who is medically free?
What is the best next step in managing a 34-year-old woman, gravida 3 para 2, at 35 weeks gestation with increasing mucoid vaginal bleeding, contractions, and fetal growth restriction due to chronic hypertension, currently 8 cm dilated and 100% effaced?
What are the causes of placental insufficiency?
What is the exact name of the MRI to order for quantitative liver and pancreatic iron assessment using a multi‑echo gradient‑echo T2* / R2* sequence?
What is the recommended protocol for inducing labour at ≥37 weeks in a singleton, cephalic pregnancy without maternal or fetal contraindications, including cervical ripening, oxytocin infusion, and management of complications?
What is the appropriate treatment for acute bacterial parotitis?
Why does taking 3 mg eszopiclone (Lunesta), 20 mg doxepin, and 8 mg ramelteon cause drowsiness, and how should I adjust the regimen?
How should a patient with a serum potassium of 3.3 mmol/L (mild hypokalemia) be managed?
What is the recommended medication management for an acute ischemic stroke patient in the emergency department who is outside the intravenous alteplase (tPA) window and also outside the large vessel occlusion (LVO) window?
Is an HbA1c of 5.9% diagnostic for diabetes?
Can history and physical examination (PE) alone provide a definitive diagnosis of aortic stenosis?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question