Ultrasonographical features of morbidly-adherent placentas

Morbidly-adherent placentas manifest as placenta accreta, increta or percreta, depending on the depth of placental invasion. These conditions present high risks of severe obstetrical haemorrhage at delivery. The underlying pathology is due to defects in the decidua basalis caused by a variety of insults, such as previous surgery, excessive curettage or infection. The incidence of morbidly-adherent placentas is rising as the frequency of caesarean sections increase. Imaging plays an important role in the antenatal detection of this condition. Based on the case series seen at our local institution, we describe the imaging characteristics of this condition as seen on grayscale ultrasonography, colour/power Doppler ultrasonography, three-dimensional ultrasonography and magnetic resonance imaging.