Purpose of review: The purpose of this review was to review the literature on the performance of ultrasound for the visualization of the placental cord insertion (PCI) and for the diagnosis of abnormal placental cord insertion (APCI). APCI included both marginal cord insertion (MCI) and velamentous cord insertion (VCI) PCI.
Recent findings: The overall rate of visualization of the PCI across all trimesters is 90.3% and for those studies routinely using color Doppler, 98.1% (P < 0.0001). Although the visualization was lower with advancing gestational age, it remained high even into the late third trimester. In all studies, where time was reported, the PCI was visualized in most cases in less than 1 min. Ultrasound performed best for the diagnosis of VCI with a sensitivity, specificity and positive predictive value of 100, 99.9 and 85.7%, respectively, with routine use of color Doppler.
Summary: Ultrasound is an excellent screening test for the evaluation of PCI across all trimesters. The use of color Doppler increases the rate of visualization and should be routinely used. Ultrasound with color Doppler is also an excellent screening test for the diagnosis of VCI. However, the performance of ultrasound is reduced with the inclusion of MCI.