[Velamentous insertion of the umbilical cord--diagnosis and management]

To assess the feasibility of ultrasound to identify velamentous insertion of the umbilical cord in B-mode, combined with Color/Power Doppler and 3D Power Angio Doppler during routine obstetric ultrasound follow up.

This was a prospective cross-sectional ultrasound study in 145 second and third trimester high-risk singleton pregnancies. Color/Power Doppler ultrasound was done in all cases to identify the placental cord insertion site. Evaluation with three-dimensional (3D) ultrasound combined with Power Doppler (3D Power Angio Doppler) was also performed in all cases with suspected velamentous insertion.

The insertion placental site of the umbilical cord was identified in 143/145 (98.6%) cases by conventional gray-scale ultrasound, combined with Color/Power Doppler. Visualization was not accomplished in 2 third trimester cases (beyond 30 w.g.) with a posterior placenta, intrauterine growth restriction (IUGR) and tendency of oligohydramnios. Velamentous insertion of the umbilical cord was suspected prenatally in 9 cases, including 2 cases with vasa previa. Three-dimensional ultrasound was of little clinical value and compared poorly with conventional gray-scale and Color Doppler imaging.

Velamentous insertion of the umbilical cord can be reliably detected prenatally by gray-scale and Color/Power Doppler ultrasound. Three-dimensional imaging has limited clinical value in the evaluation of the placental cord insertion site. Its systematic assessment during routine obstetric ultrasound follow up has the potential of identifying most pregnancies with velamentous insertion and, therefore, those at risk for some important obstetric complications, including vasa previa.