PITFALLS IN THE DIAGNOSIS OF

UMBILICAL CORD INSERTION

1. A marginal cord insertion may appear normal in one plane and marginal in a second perpendicular plane.
2. Cord vessels must be identified as dividing in the placental parenchyma and not merely lying adjacent to the placenta.
3. Superficial placental vessels may resemble cord vessels (one must therefore follow the umbilical cord vessels into the amniotic cavity).
4. Color doppler can assist gray scale images if the exact site of insertion cannot be demonstrated.
5. If the site of insertion is not identified, transabdominal or transvaginal images of the lower uterine segment should be obtained. This will help exclude a vasa previa.
6. A normal appearing cord insertion does not exclude a vasa previa if the placenta has a succenturiate lobe.