Review Management of large-forgestational-age pregnancy in non-diabetic women TOG

 

Terminology 📖

• Large-for-Gestational-Age (LGA):
  • Fetuses or newborns with an (estimated) weight >90th percentile or 2 SD from the mean for gestational age.
• Ponderal Index:
  • Indicates body proportions: weight divided by the third power of length (g/cm³).
• Macrosomia:
  • Newborns with a birth weight above specific limits (no universal consensus).
  • Common definitions:
    • Birth weight ≥4000g, ≥4200g, or ≥4500g.
  • Generally, it seems appropriate to consider a fetus or newborn with an estimated or actual birth weight 4000 g as macrosomic,6,9 especially in cases of insulindependent diabetes mellitus
• In this article, we will define LGA fetuses as those with an (estimated) birth weight 4500 g

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Risk Factors and Obstetric Complications 🩺

• Risk Factors:
  • Male infant sex, multiparity, maternal age (30–40 years), white race, diabetes, and gestational age >41 weeks. 📅
• Complications:
  • Higher rates of cesarean delivery, shoulder dystocia, chorioamnionitis, fourth-degree perineal lacerations, postpartum hemorrhage, and longer hospital stay.
  • Adjusted odds ratios for cesarean births by weight:
    • 4000–4499g: 1.69.
    • 4500–4999g: 2.99.
    • ≥5000g: 5.46. 🚨
  • Odds ratios for shoulder dystocia by weight:
    • 4000–4499g: 6.29.
    • 4500–4999g: 13.05.
    • ≥5000g: 17.52.
• No significant adverse outcomes were noted between birth weights of 3500–3999g and 4000–4499g.
• High (4500–4999g) and very high (≥5000g) birth weights are linked to:
  • Neonatal death (mainly due to asphyxia).
  • Increased risk of sudden infant death syndrome (SIDS) in very high birth weights.

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Long-Term Health Risks 🧬

• Type 2 Diabetes:
  • U-shaped risk: Higher risk with both low birth weight (<2500g) and high birth weight (>4000g).
• Breast Cancer:
  • Larger size at birth (length, head circumference) linked to increased risk in premenopausal women.
• Asthma in Childhood:
  • High birth weights associated with more emergency visits for asthma.
  • For every 100g increase in birth weight ≥4500g, there’s a 10% rise in emergency visits.
• Obesity:
  • High birth weights linked to childhood and young adult obesity/BMI.
  • No strong correlation with middle-aged adults. Genetic factors are significant.

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Diagnosis of Fetal Macrosomia 🩻

• Clinical Estimation:
  • Based on fundal height and uterine palpation, both prone to variations.
  • Influenced by factors like:
    • Maternal size, amniotic fluid volume, bladder status, pelvic masses (e.g., fibroids), and fetal position.
• Fundal Height Measurements:
  • Adjusted for maternal variables (age, BMI, parity) improve LGA detection:
    • Detection rate in adjusted group: 46% vs. 24% in control.
    • Cost-effective when performed serially. 💰
• Ultrasonography:
  • Measures include abdominal circumference and estimated fetal weight (EFW).
  • Sensitivity and predictive value are low, especially for higher birth weights.
  • Combining EFW and amniotic fluid index (AFI) improves prediction accuracy.
• Emerging Tools:
  • Serial sonographic measurements, 3D ultrasound, MRI, and customized fetal growth charts enhance accuracy.

  • Ultrasonographic Prediction of Fetal Macrosomia 🩺

    • Ultrasound measures:
      • Includes single parameters (e.g., abdominal circumference or subcutaneous tissue thickness).
      • Combination of measurements used to estimate fetal weight. 📏
    • Challenges:
      • Ultrasound biometry for detecting fetal weight ≥4000g:
        • Low sensitivity, low positive predictive value, and high negative predictive value.
    • Systematic review:
      • Analyzed 63 accuracy studies (51 on EFW, 12 on fetal abdominal circumference).
      • Included data from 19,117 women.
      • Findings:
        • Summary receiver operating characteristic curve (sROC):
          • EFW area: 0.87.
          • Abdominal circumference area: 0.85 (p = 0.91).
          • No significant difference in prediction accuracy. 📊
        • Likelihood ratios (LRs) for predicting birth weight ≥4000g:
          • Positive test: LR = 5.7 (95% CI: 4.3–7.6).
          • Negative test: LR = 0.48 (95% CI: 0.38–0.60).
    • Key Points:
      • Positive test results are more accurate for ruling in macrosomia.
      • ROC curves show soft tissue measurements are not superior to clinical or other sonographic predictions. 📉
      • Combined amniotic fluid index (AFI) and EFW measurements during mid-third trimester:
        • Positive predictive value: 85%.

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    Other Predictors of Macrosomia 🩻

    • Maternal BMI:
      • A BMI increase of ≥25% during pregnancy:
        • Sensitivity: 86.2%.
        • Specificity: 93.6%.
        • Positive predictive value: 71.4%.
        • Negative predictive value: 97.45%.
    • History of macrosomic infants:
      • Increased risk in subsequent pregnancies:
        • Higher risk for women with two or more macrosomic infants.

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    Management of Suspected Fetal Macrosomia 🛠️

    General Approach:

    • Elective Cesarean Section:
      • Aims to prevent complications like brachial plexus injuries and maternal perineal lacerations.
      • Estimated:
        • 3,600 cesarean deliveries needed to prevent one permanent brachial plexus injury for suspected macrosomia ≥4500g.
      • Not justified solely for macrosomia <5000g. 🚨
      • Recommended only if EFW ≥5000g.
    • Labour Induction:
      • Initially used to prevent cephalopelvic disproportion and associated risks.
      • Meta-analysis (Sanchez-Ramos et al.):
        • Labour induction increases cesarean rates without improving perinatal outcomes.
        • Expectant management shows better outcomes. ✅
    • Nulliparity:
      • Independently associated with higher cesarean risk compared to multiparity.

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    Algorithms for Antenatal Management 🧑‍⚕️

    

    
    

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    Intrapartum Management:

    • First Stage:
      • Establish IV line and ensure continuous monitoring.
      • Regular cervical assessment; augment with oxytocin if needed.
    • Second Stage:
      • Early cesarean for lack of descent.
      • Ensure senior staff presence. 👩‍⚕️
    • Third Stage:
      • Active management to prevent postpartum hemorrhage (e.g., Syntometrine® injection).
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    Special Circumstances ⚠️

    Previous Cesarean Section:

    • Elective cesarean not always necessary for suspected macrosomia.
    • Vaginal delivery success depends on:
      • Previous vaginal birth, BMI, and cesarean indication. 🚑

    Shoulder Dystocia:

    • Higher recurrence risk (1.1–16.7%).
    • Brachial plexus injuries:
      • Mostly transient.
      • Mode of delivery does not eliminate risk.

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    Conclusion 🏁

    • Ultrasound-based diagnosis should not solely determine management.
    • Evidence does not support routine labour induction or elective cesarean for non-diabetic macrosomia <5000g.
    • A holistic approach combining clinical judgment, maternal history, and preparedness is essential.
    • Emphasis on efficient management of shoulder dystocia and informed decision-making. 🩺
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