Abruptio placentae occurs in all except:
Abruptio placenta is premature separation of normally situated placentaQ resulting in hemorrhage.
Risk factors:

Increased maternal age - Increased parity
Pre eclampsia - Chronic hypertension
Preterm ruptured membranes pregnancy - Sudden uterine decompression as in hydramnios and twin
Cigarette smoking - Thrombophilia
Cocaine abuse - Previous abruption
External trauma - Folic acid deficiency
Uterine leiomyoma

My – My- I pity all of you out there as you have to memorise so many lists (not only in gynae, obs but in other subjects as well). Even I have gone through the same phase. Friends I had devised a simple method to learn these lists. For some lists, I used to draw diagrams and then at the time of exam that diagram was reproduced in my mind. Try it out for yourself. e.g.
Smokers
Alcoholics
PET
Folic acid deficiency