Detachment of the placenta from the wall of the womb during pregnancy. It is caused by bursting of an artery at the point where the placenta joins the uterus; the increasing discharge of blood wholly or partially detaches the placenta from the uterine wall. Detachment of the placenta is associated with sudden, continuous and often severe pain in the lower abdomen. The uterus hardens as a result of the violent contraction, and does not relax. The baby can no longer be felt, and its heartbeat cannot be heard. With a major detachment, blood supply to the baby ceases, causing its death within a short time.