What causes placental abruptions?

Placenta separating: Placenta abruption is when the placenta separates from the uterus. It can happen after a traumatic event like a car accident. It can occur in women with high blood pressure or in women who use drugs like Cocaine and methamphetamine. Autoimmune diseases like lupus increase risk as do clotting disorders like antiphospholipid antibody syndrome.

High BP, trauma, ROM: Abruptio placentae (formal term) occurs when there is separation of placenta from the wall of the uterus. The diagnosis depends on there being a normally placed placenta (eg, not one covering the cervix). There may or may not be bleeding early. Common causes include high blood pressures, trauma to the abdomen, rapid loss of amniotic fluid (eg, in cases of multiple pregnancy or excess fluid).

Meds, medical causes: Women with some autoimmune conditions are at higher risk for placental abruption. Also a very active labor, like that brought on by some stimulant drugs, can lead to abruption. A more chronic form of abruption can occur in women who have had preterm premature rupture of membranes for long periods of time.

Mostly unknown: Believe it or not, the cause for a large number of placental abruptions is never determined. In those cases where a cause is determined, the most common are: hypertension; smoking; trauma, such as a car accident; Cocaine use; and a history of a previous placental abruption.

Several things: Any severe trauma, smoking, high blood pressure, twins, are some causes of placental abruption.

Placenta abruption: While frequently the cause of placental abruption is unknown; a recognized cause is a placenta that covers the cervical canal. The placental may cover the cervix in early pregnancy, and then move or migrate upwards freeing up the entrance to the birth canal. This can be followed by sonograms avoiding a c-section. A placenta that covers the birth canal is a risk to abrupt or shear off during labor.