The exact pathogenesis of placental abruption is unclear and is probably related to vascular lesions, mechanical factors, sudden decrease in intrauterine pressure, etc. Pregnant women suffering from hypertensive disorders of pregnancy, etc., lead to vascular lesions throughout the body, hemorrhage of the capillaries of the underlying meconium, formation of hematomas, etc., leading to abruption of the placenta. External trauma and sudden decrease in uterine pressure can induce uterine contraction or stretching, resulting in misalignment of the placenta with the uterine wall, which can further lead to placental abruption. The incidence of placenta previa is also increased by other causes, such as advanced age, multiple births, smoking, drug use, chorioamnionitis, etc. The probability of placenta previa is also increased in pregnant women who undergo assisted reproduction technology (ART). Pregnant women with a history of placenta previa can also be at increased risk of recurrent placenta previa.