10-25 % Placental abruption, or the separation of the placenta from its site of implantation before the delivery of the fetus, averages 1 in 200 deliveries. Once a woman has suffered an abruption, the risk in a future pregnancy increases as much as 10-25%. Risk factors for abruption include maternal age, cigarette smoking, coexisting hypertension, preeclampsia and premature rupture of membranes.
Abruption. First of all depends what caused in in the first place(drugs, accidents, high blood pressure) . If no identifiable cause you are still at increased risk for placenta abruption. The risk is higher than 1 %.What you can do is avoid potential causes for abruption, keep your appointments and follow your doctor advices:).