Unfortunately, not many cases of placental abruption can be diagnosed prior to the hemorrhage and, in most cases, we only guess at what may have precipitated the placental separation. The incidence of this condition is about 1 in 125 to 150 pregnancies but there are many different degrees of abruption. Unfortunately, the baby is lost in about 20 percent of such cases. This condition seems to be increasing in frequency in the United States but the severity is decreasing at some sites. Sadly, even if the baby lives, many have lifelong disabilities due to the diminished blood flow during the crisis.
Incidence increases with parity and age and is more common in African-American women.
By far, the most commonly associated condition is either pregnancy induced hypertension or chronic hypertension. When the abruption occurs early in gestation, the most common reason for the occurrence is associated with preterm premature rupture of the amniotic membranes. Sudden decompression may also cause premature placental separation such as occurs when one twin is delivered and the other one is still in the uterus. External trauma that might occur with abuse or accidents may cause this condition. Uterine fibroids may also predispose one to abruption.