Placental cord insertion visualization with prenatal ultrasonography.

Color Doppler and gray scale sonography can be used prenatally to identify the location of the cord insertion into the placenta. The purposes of this paper were to (1) relate sonographic identification of placental cord insertion with placental pathology; (2) evaluate the possibility that a marginal cord insertion may evolve into a velamentous cord insertion; and (3) determine the frequency and factors affecting sonographic visualization of cord insertion. Our results show that the sonographic assessment of cord insertion correlated with the pathologic outcome in 83% (106 of 128) of singleton pregnancies and at least one of the fetuses in 72% (8 of 11) of twin or triplet pregnancies. Although the sensitivity for identification of an abnormal cord insertion was low (42%), the specificity was high (95%). Our data suggest that marginal cord insertion evolved into velamentous cord insertion in one singleton and one twin. Our results showed that cord insertion was visualized in 54% of fetuses scanned in a routine clinical practice. Cord insertion visualization was possible at all gestational ages, although it was more difficult at later gestational ages. In conclusion, this study provides evidence that (1) ultrasonography (either gray scale or color Doppler) is useful in identifying normal, marginal, and velamentous cord insertion; (2) marginal cord insertion may evolve into velamentous cord insertion as pregnancy progresses; (3) in clinical practice the cord insertion site was visualized in just over half of the cases, and (4) prenatal identification of marginal and velamentous cord insertion potentially may be useful for planning obstetrical management.