Placenta accreta is a rare condition. Its incidence is constantly increasing due to the increasing number of caesarean sections (multiplied by four over the same period).Placenta accreta is responsible for major maternal morbidity and mortality. Targeted ultrasound, in the presence of risk factors, is relevant for this diagnosis. Patients with at least one uterine scar and a previous placenta previa represent a population at risk whose placenta should be examined during screening ultrasound with the full attention of the operator. The smallest diagnostic doubt should lead the practitioner to refer the patient for expert ultrasound examination. Current challenges include early detection of placenta accreta in the first trimester, prediction of the degree and extent of placental villi invasion, and prognosis assessment.