What condition is defined by the abnormal placement of the placenta, potentially leading to excessive bleeding?

The condition defined by the abnormal placement of the placenta is placenta previa. This occurs when the placenta is positioned low in the uterus, covering part or all of the cervix. This abnormal placement can lead to complications during pregnancy and delivery, particularly the risk of excessive bleeding when labor begins or during delivery. As the cervix dilates, the placenta can separate from the uterine wall, leading to bleeding that can be dangerous for both the mother and the baby.

Placenta accreta, while a serious condition, involves the placenta growing too deeply into the uterine wall rather than being improperly positioned. Placenta abruption refers to the premature separation of the placenta from the uterus, which also poses significant risks but is a different issue from abnormal placement. Uterine atony involves a lack of muscle tone in the uterus following delivery, leading to heavy bleeding, but is not related to the placement of the placenta during pregnancy. Understanding these distinctions is crucial in managing pregnancy-related complications effectively.