Various Doppler sonographic appearances and challenges in prenatal diagnosis of vasa praevia

Rupture of vasa praevia is associated with a high rate of fetal or neonatal mortality. Since the recent development of color and spectral Doppler sonography, prenatal diagnosis of vasa praevia has been increasing but is not yet consistent. We report 2 cases that were diagnosed prenatally, enabling cesarean section to be performed under optimal conditions to prevent complications. A better knowledge of the characteristic Doppler sonographic appearances and the risk factors associated with vasa praevia could greatly facilitate the prenatal diagnosis of this condition and hence the fetal prognosis.