Imaging techniques to identify morbidly adherent placenta praevia: a prospective study.

The objective of this study was to assess the sensitivity and specificity of Gray scale ultrasonography, magnetic resonance (MRI) and colour flow Doppler imaging in the diagnosis of morbidly adherent placenta praevia. We collected prospectively 30 cases of placenta praevia diagnosed by Gray scale ultrasound, colour flow Doppler and MRI. Delivery by elective caesarean section was carried out at the 38th week, before the onset of labour, unless obstetric complications supervened. Data regarding maternal outcome and newborn status were collected. Three patients had a morbid adherence of the placenta at delivery, two of whom required caesarean hysterectomy, and the other an internal iliac artery ligation. One patient was delivered at 33 weeks' gestation due to uncontrollable bleeding and the remainder were delivered at 38 weeks. All mothers and infants were well at the time of discharge. Colour flow Doppler was shown to be more specific in the diagnosis of the morbidly adherent placenta praevia than MRI. Doppler had a negative predictive value of 95%.