Placental abruption, also known as abruptio placentae, is a serious obstetric complication in which a normally situated placenta separates partially or completely from the uterine wall before the birth of the baby. Because the placenta is the main organ responsible for the exchange of oxygen and nutrients between the mother and fetus, premature separation can rapidly compromise fetal oxygenation and may cause significant maternal blood loss. It usually occurs after 20 weeks of pregnancy and is an important cause of antepartum haemorrhage, maternal morbidity, fetal distress and perinatal mortality. The clinical presentation varies according to the degree of placental separation, the location of the bleeding and whether the blood escapes through the vagina or remains concealed behind the placenta. The exact cause of placental abruption is not always identifiable. In many cases, it results from damage to the maternal blood vessels supplying the placenta. Rupture of these vessels causes bleeding into the decidua, and the collection of blood may gradually separate the placenta from the uterine wall. Several maternal, obstetric and environmental factors can increase the risk of this process. One of the most important risk factors is maternal hypertension. Chronic hypertension and pregnancy-induced hypertension, particularly preeclampsia, are strongly associated with placental abruption. Persistent high blood pressure can damage the small blood vessels of the placenta and increase the likelihood of haemorrhage and separation. Previous history of placental abruption is another important risk factor. A woman who has experienced abruption in a previous pregnancy has a higher risk of recurrence in a subsequent pregnancy. Trauma to the abdomen can also cause placental separation. Motor vehicle accidents, falls, blows to the abdomen and physical injuries may produce shearing forces between the placenta and uterine wall. The risk is particularly significant when trauma is severe. Sudden decompression of the uterus, such as after rupture of membranes in the presence of excessive amniotic fluid, may also contribute to placental separation. Premature rupture of membranes, especially when it occurs before term, is associated with an increased risk of placental abruption. Loss of amniotic fluid may alter the size and shape of the uterus and create conditions that favour separation of the placenta. Polyhydramnios followed by sudden rupture of membranes can similarly produce rapid uterine decompression. Maternal smoking is another recognized risk factor. Tobacco exposure can produce vascular changes and reduce placental blood flow, increasing the risk of placental complications. Cocaine and other stimulant drug use can cause marked vasoconstriction and hypertension and is strongly associated with placental abruption. Therefore, substance use during pregnancy is an important factor to assess during antenatal care. Advanced maternal age and high parity may also increase the risk. The risk is higher in women with several previous pregnancies, particularly when other risk