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

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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Abnormal Placental Cord Insertion

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