Abnormal Placentation: Placenta Previa, Vasa Previa, and Placenta Accreta

Obstet Gynecol. 2015 Sep;126(3):654-668. doi: 10.1097/AOG.0000000000001005.


Placental disorders such as placenta previa, placenta accreta, and vasa previa are all associated with vaginal bleeding in the second half of pregnancy. They are also important causes of serious fetal and maternal morbidity and even mortality. Moreover, the rates of previa and accreta are increasing, probably as a result of increasing rates of cesarean delivery, maternal age, and assisted reproductive technology. The routine use of obstetric ultrasonography as well as improving ultrasonographic technology allows for the antenatal diagnosis of these conditions. In turn, antenatal diagnosis facilitates optimal obstetric management. This review emphasizes an evidence-based approach to the clinical management of pregnancies with these conditions as well as highlights important knowledge gaps.

Publication types

  • Comparative Study
  • Review

MeSH terms

  • Adult
  • Cesarean Section / methods
  • Evidence-Based Medicine
  • Female
  • Humans
  • Hysterectomy / methods
  • Infant, Newborn
  • Placenta Accreta / diagnostic imaging*
  • Placenta Accreta / surgery
  • Placenta Previa / diagnostic imaging*
  • Placenta Previa / surgery
  • Pregnancy
  • Pregnancy Complications / diagnostic imaging
  • Pregnancy Complications / surgery
  • Pregnancy Outcome*
  • Pregnancy Trimester, Second
  • Risk Assessment
  • Severity of Illness Index
  • Treatment Outcome
  • Ultrasonography, Prenatal / methods*
  • Uterine Hemorrhage / diagnosis
  • Uterine Hemorrhage / etiology
  • Vasa Previa / diagnostic imaging*
  • Vasa Previa / surgery