What condition involves the detachment of the placenta from the uterus before delivery?

Abruptio placenta, the correct answer, refers to the premature detachment of the placenta from the uterine wall before the fetus is delivered. This condition can lead to significant maternal and fetal complications, including bleeding and fetal distress, due to the disruption of the blood supply to the fetus. It typically occurs in the third trimester and can be triggered by factors such as trauma, hypertension, or preeclampsia.

Understanding this condition is crucial in obstetrics, as it requires immediate medical attention to manage the risk of maternal and fetal morbidity or mortality. Contrast this with other conditions listed in the options: ovarian torsion is related to the twisting of the ovary, leading to pain and possible loss of the ovary, spontaneous abortion refers to the loss of a pregnancy before 20 weeks, typically due to chromosomal abnormalities or other issues, and placenta previa is characterized by the placenta being positioned over the cervix, which can lead to bleeding but does not involve premature detachment. Each of these conditions has distinct clinical presentations, causes, and management strategies, highlighting the importance of accurate diagnosis in obstetric care.