Abnormal Placental Cord Insertion

Abnormal Placental Cord Insertion
Roya Sohaey, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Marginal Cord Insertion
  • Velamentous Cord Insertion (VCI)
Less Common
  • Umbilical Cord Cyst
  • Vasa Previa (VP)
Rare but Important
  • Umbilical Cord Aneurysms
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
  • Placental cord insertion (PCI) identification
    • Easily achievable
      • Seen in almost 100% 2nd trimester cases
      • More difficult if posterior placenta and 3rd trimester fetus
    • Use grayscale first
      • Find general area of PCI
      • Less motion artifact than Doppler
    • Use color Doppler to confirm
      • Rule out adjacent cord
      • Show insertion and branching vessels
      • All vessels should be on fetal surface of placenta
      • Rule out submembranous vessels
    • Use pulsed Doppler to show fetal flow
      • Low resistive arterial flow
      • Document fetal heart rate
  • Look for PCI routinely in high risk cases
    • Monochorionic twins
    • Placenta previa
    • Succenturiate lobe
    • Abnormally large or small placenta
    • Intrauterine growth restriction
    • Anomalous fetus
  • Use Doppler to make a specific diagnosis
    • Look for submembranous vessels
      • Velamentous cord
      • Vasa previa
    • Cyst versus aneurysm
      • Identical appearance without color Doppler
    • Use pulse Doppler
      • Differentiate maternal from fetal vessels
Helpful Clues for Common Diagnoses
  • Marginal Cord Insertion
    • PCI is within 2 cm of placental edge
    • Good prognosis if isolated finding
    • Sometimes associated with other placental abnormalities
      • Small placenta
      • Unusually thick placenta (Battledore)
      • Monochorionic twinning
      • Abruption
      • Intrauterine growth restriction
    • Progression to velamentous cord insertion
      • Rare complication
      • More likely if PCI is < 5 mm from margin
      • Follow-up scans indicated
  • Velamentous Cord Insertion (VCI)
    • Membranous cord insertion
      • VCI is often adjacent to placenta
      • Some or all vessels are submembranous
      • VCI may be seen between two placental lobes
    • Atypical vessel appearance from lack of placental support
      • Dilated vessels
      • Excessively separated vessels
    • Doppler essential for diagnosis
      • Helps identify VCI
      • Shows vessels extending from VCI to placenta
      • Pulsed Doppler proves vessels are fetal
Helpful Clues for Less Common Diagnoses
  • Umbilical Cord Cyst
    • 33% of all UC cysts are at PCI
      • Other 2/3 are mid cord or near fetus
    • Often multiple and clustered at PCI
    • PCI cysts are less likely to resolve
      • First trimester UC cysts often resolve
    • Rare complication includes intracystic hemorrhage
      • May lead to cord compromise
    • Rarely associated with fetal anomalies and aneuploidy
      • Genitourinary anomalies
      • Trisomy 18
      • Amniocentesis probably not necessary if isolated finding in low risk patient
  • Vasa Previa (VP)
    • Submembranous fetal vessels near internal cervical os
      • Within 2 cm of os considered VP
    • VP from succenturiate lobe
      • Most common etiology
      • Communicating vessels between main lobe and succenturiate lobe located near internal cervical os
      • Associated with low lying placenta (primary or succenturiate)
    • Vasa previa from VCI
      • Low lying placenta with VCI
      • Velamentous vessels near internal cervical os
    • Prenatal diagnosis is imperative
      • 60-80% fetal mortality associated with missed diagnosis
      • Fetal exsanguination with cervical dilatation
Helpful Clues for Rare Diagnoses
  • Umbilical Cord Aneurysms
    • Umbilical artery (UA) aneurysm
      • Most common location is at PCI
      • Saccular dilatation of UA
      • May have arteriovenous fistula to umbilical vein
      • Associated with single umbilical artery, fetal anomalies and trisomy 18
      • Best prognosis if isolated finding
    • Umbilical vein (UV) varix
      • Most common location is intraabdominal in fetus
      • Rarely in free floating loops of cord
      • Associated with increased venous pressure and hydrops
      • Rarely can thrombose or rupture
Other Essential Information
Tags:
Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Abnormal Placental Cord Insertion

Full access? Get Clinical Tree
Get Clinical Tree app for offline access