Placenta previa6

Chronic hypertension

Multiparity

Multiple gestations

Older age

Previous cesarean delivery

Tobacco use

Uterine curettage

Placental abruption8–10

Chronic hypertension

Multiparity

Preeclampsia

Previous abruption

Short umbilical cord

Sudden decompression of an overdistended uterus

Thrombophilias

Tobacco, cocaine, or methamphetamine use

Trauma: blunt abdominal or sudden deceleration

Unexplained elevated maternal alpha fetoprotein level

Uterine fibroids

Vasa previa11

In vitro fertilization

Low-lying and second trimester placenta previa

Marginal cord insertion

Multiple gestation

Succenturiate-lobed and bilobed placentas