The International Postpartum Hemorrhage Collaborative Group has observed an increasing trend in postpartum hemorrhage (PPH) and its severity in a number of high-resource countries including the UK, Australia, Canada, and the United States. Antenatal optimization of hematinic status may avoid the need for transfusion should a hemorrhage occur. This is particularly important for women with identified risk factors or who refuse blood. Early recognition of physiological derangement is vital and modified obstetric early warning systems, tracking changes in maternal physiology, have been introduced. The physiological changes of pregnancy initially buffer the effects of hemorrhage, so early signs such as tachycardia, decreased urine output and tachypnoea should be sought. The aim is to resuscitate the patient by stopping the bleeding and restoring a circulating blood volume with oxygen-carrying potential. Placenta accreta is most commonly associated with a combination of a low-lying placenta and uterine trauma from an earlier cesarean section (CS).

Obstetric complications secondary to placental dysfunction can occur at any point in gestation. Improvements in perinatal diagnostic techniques such as focused ultrasound studies of fetal growth, placental blood flow, and fetal/placental anatomy now permit the identification of certain complications related to poor implantation or abnormal early development that can be linked to placental function. Confusion caused by the potential overlap in history and physical findings with the various placental abnormalities has led physicians in recent years to rely heavily on ultrasound scanning to help in identifying the cause of ante- and intrapartum hemorrhage. With the known association of placenta previa and prior cesarean delivery with placenta accreta, and an ever-increasing rate of cesarean delivery, there has been a recent focus on identifying ultrasound findings predictive of abnormal placenta adherence. Placental abnormalities can lead to maternal adverse outcomes such as hemorrhage requiring transfusion, more extensive surgery, emotional consequences, and even death.