Management of Large for Gestational Age Fetus ; Scientific Impact Paper No. XX Peer Review Draft – February 2018

Scientific Impact Paper No. XX

Peer Review Draft – February 2018

Management of Large for Gestational Age (LGA) Fetus

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Management of Pregnancies with Suspected Macrosomia

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Background

📝 Definition:

• Macrosomia: Neonatal birthweight >4000 g (common cut-off), or >4500 g and >5000 g in some definitions.
• Large for Gestational Age (LGA): Fetal weight >90th percentile for gestational age.

📊 Prevalence:

• Macrosomia: Occurs in ~10% of pregnancies.
• Elective Cesarean Section (CS): Recommended for:
  • Diabetic pregnancies: EFW ≥4500 g.
  • Non-diabetic pregnancies: EFW ≥5000 g.

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Risks

Maternal Risks:

• 🏥 Emergency CS: Risk increases with weight.
• 🩸 Postpartum Hemorrhage (PPH): Nearly doubles with neonates >4000 g.
• 🧵 Perineal Trauma: 3-4x higher risk with macrosomic neonates.

Neonatal Risks:

• 💔 Shoulder Dystocia: 20x higher risk in macrosomic neonates.
• 🦴 Brachial Plexus Injury: 1.3–1.5/1000 births, 20x higher with macrosomia.
• 🦴 Clavicle or Humerus Fractures: 10x higher risk in neonates >4000 g.
• 🧠 Hypoxia-Related Complications: Includes cerebral palsy and neurological damage (23% incidence with severe injury).

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Risk Factors

Maternal:

• ⚖️ High BMI:
  • Overweight (BMI 25–30): 1.5x increased risk.
  • Obese (BMI >30): 2x increased risk.
• 🤰 Multiparity:
  • Grand multiparous women: 1.9x increased risk.
  • History of macrosomic neonates: 10-15x increased recurrence risk.
• 🍭 Diabetes:
  • Pre-existing diabetes: 1.7–1.8x increased risk.
  • GDM or high fasting glucose: 2-3x increased risk.

Fetal:

• 🧬 Genetic Predisposition: Influences size.

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Antenatal Care (ANC)

Screening Methods:

• 📏 Symphysis Fundal Height (SFH):
  • Modest detection rate (38%); 12% false-positive rate.
  • Ineffective in obese mothers.
• 📷 Ultrasound Biometry:
  • Superior to clinical methods for predicting LGA.
  • Two-Stage Screening:
    • Routine scan at 35–37 weeks.
    • Follow-up scan at 39–40 weeks for high-risk pregnancies.

Counseling:

• 📄 Provide clear verbal and written information on:
  • Risks associated with macrosomia.
  • Delivery options: Induction of Labor (IOL) vs. Elective CS.

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Intrapartum (IP) Management

Delivery Options:

• 🏥 Elective CS:
  • Recommended for:
    • Diabetic pregnancies with EFW ≥4500 g.
    • Non-diabetic pregnancies with EFW ≥5000 g.
• 🔄 Induction of Labor (IOL):
  • Reduces risks:
    • Shoulder dystocia: 40% reduction.
    • Fractures: 80% reduction.
  • Does not increase CS rates for macrosomic fetuses.

Complications to Monitor:

• ⏳ Prolonged Labor:
  • Higher risk with macrosomic fetuses (OR 1.57–2.03).
• 💔 Shoulder Dystocia:
  • Prevalence increases exponentially with fetal weight.

Emergency Preparedness:

• 👩‍⚕️ Skilled obstetric team for complications.
• 🔍 Continuous fetal monitoring during labor.

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Postpartum (PP) Management

Maternal Care:

• Monitor for:
  • 🩸 PPH and uterine atony.
  • 🧵 Perineal trauma and long-term issues (e.g., prolapse, incontinence).

Neonatal Care:

• Assess for:
  • 🦴 Birth injuries (e.g., fractures, brachial plexus injury).
  • 🍭 Hypoglycemia and hypoxia-related complications.

Follow-Up:

• 📝 Document delivery outcomes and complications.

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Management of Pregnancies with Suspected Macrosomia

Key Findings:

• 🔎 Strong association with adverse outcomes for mother and neonate.
• 📷 Ultrasound: Superior to SFH for antenatal prediction.
• Routine Scans:
  • At 35–37 weeks, followed by 39–40 weeks for high-risk pregnancies.
• 🔄 IOL for EFW >4000 g: Reduces complications without increasing CS rates.

Recommendations:

• ⚠️ Identify women with risk factors (high BMI, multiparity, diabetes) early.
• 🗂️ Provide clear, evidence-based information on delivery options.
• 🏥 Elective CS: Preferred for:
  • EFW ≥4500 g (diabetic pregnancies).
  • EFW ≥5000 g (non-diabetic pregnancies).