Definition of Placenta abruptio:

Placenta abruptio is separation of the placenta (the organ that nourishes the fetus) from the site of uterine implantation before delivery of the fetus.

Causes, incidence, and risk factors:

The exact cause of a placetal abruption may be difficult to determine.

Direct causes are rare, but include:

• Abnormally short umbilical cord
• Injury to the belly area (abdomen) from a fall or automobile accident
• Sudden loss in uterine volume (can occur with rapid loss of amniotic fluid or the delivery of a first twin)

Risk factors include:

• Advanced maternal age
• Cigarette smoking
• Cocaine use
• Diabetes
• Drinking more than 14 alcoholic drinks per week during pregnancy
• High blood pressure during pregnancy -- About half of placental abruptions that lead to the baby's death are linked to high blood pressure
• History of placenta abruptio
• Increased uterine distention (as may occur with multiple pregnancies or abnormally large volume of amniotic fluid)
• Large number of prior deliveries

Placenta abruptio, including any amount of placental separation prior to delivery, occurs in about 1 out of 150 deliveries. The severe form, which results in fetal death, occurs only in about 1 out of 500 to 750 deliveries.