Polyhydramnios

Polyhydramnios
Roya Sohaey, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Idiopathic
  • Macrosomia
  • Diabetes
  • Hydrops
  • Twin-Twin Transfusion Syndrome
  • Fetal Bowel Obstruction
Less Common
  • Arthrogryposis, Akinesia Sequence
  • Skeletal Dysplasia, Severe
  • Chorioangioma
  • Cystic Adenomatoid Malformation
Rare but Important
  • Mesoblastic Nephroma
  • Unilateral Ureteropelvic Junction Obstruction
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
  • Amniotic fluid index (AFI)
    • Divide uterus into 4 equal quadrants
    • Measure maximum vertical pocket (MVP)
      • Avoid fetal parts/cord in MVP
    • Add the 4 MVPs to calculate AFI
    • AFI/gestational age normogram tables available
      • > 24 cm AFI = polyhydramnios
  • Twin fluid assessment
    • Measure MVP for each fetus
    • ≥ 8 cm = polyhydramnios
Helpful Clues for Common Diagnoses
  • Idiopathic
    • Most common cause (2/3)
      • Mild, stable finding
    • Normal patient and fetus
      • No diabetes or fetal anomalies
    • 28% with fetal macrosomia
  • Macrosomia
    • Estimated fetal weight > 90th percentile
    • Large abdominal circumference is a hallmark finding
      • ↑ Truncal echogenic fat
    • Causes
      • Hereditary characteristics
      • Maternal obesity
      • Diabetes
      • Beckwith-Wiedemann syndrome
  • Diabetes
    • Gestational diabetes (most common)
      • Glucose intolerance during pregnancy
      • Oral glucose tolerance test given between 24-28 wks
    • Pregestational diabetes (type 1 or 2)
    • Polyhydramnios associated with poor glucose control
      • May be first finding in pregnancy
      • Associated with macrosomia
  • Hydrops
    • Excessive fetal fluid accumulation (2 or more body cavities)
      • Anasarca
      • Pleural effusion (± pericardial)
      • Ascites
    • Amniotic fluid may be ↑ or ↓
    • Immune hydrops (10%)
      • Hemolytic disease image fetal anemia
    • Non-immune (90%)
      • Infection
      • Any cause of fetal anemia
      • Any cause of fetal heart failure
      • Lymphatic obstruction
    • Aneuploidy associations
      • Turner syndrome (cystic hygroma)
      • Trisomy 21
      • Trisomy 18
  • Twin-Twin Transfusion Syndrome
    • Monochorionic twinning
      • Artery-to-vein anastomoses in shared placenta
      • Donor twin partly perfuses recipient twin
    • Fluid discrepancy may be 1st sign of developing twin-twin transfusion syndrome (need to follow carefully)
    • Recipient twin with polyhydramnios
      • Larger twin
    • Donor twin with oligohydramnios
      • Smaller “stuck” twin
  • Fetal Bowel Obstruction
    • Late polyhydramnios (> 24 wks)
    • Esophageal atresia
      • Absent or small stomach
      • 1/3 with trisomy 18 or 21
      • Associated with VACTERL syndrome
    • Duodenal atresia
      • “Double-bubble” appearance
      • 1/3 with trisomy 21
    • Jejunal, ileal atresia
      • “Sausage-shaped” bowel loops
Helpful Clues for Less Common Diagnoses
  • Arthrogryposis, Akinesia Sequence
    • Heterogeneous group of disorders
      • Lack of extremity motion
      • Contractures
    • Polyhydramnios from ↓ fetal movement/swallowing
    • Associations
      • Trisomy 18
      • Autosomal dominant and recessive syndromes
  • Skeletal Dysplasia, Severe
    • Common dysplasias
      • Thanatophoric
      • Achondroplasia
      • Achondrogenesis
      • Osteogenesis imperfecta
    • Common skeletal findings
      • Short limbs
      • Poor ossification
      • Bowed or broken bones
      • Craniosynostosis
    • Polyhydramnios common in 3rd trimester
  • Chorioangioma
    • Benign, vascular placental tumor
    • Large masses (> 5 cm): ↑ Complications
    • Polyhydramnios
      • Transudate from leaky vessels
    • Hydrops
      • Arteriovenous shunting in mass
      • Fetal anemia from hemolysis
  • Cystic Adenomatoid Malformation
    • Lung hamartoma
    • Microcystic and macrocystic types
    • Polyhydramnios etiology
      • Esophagus compression
      • Associated with hydrops
      • Mass may make fluid
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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Polyhydramnios

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