Placenta previa is a condition of pregnancy when the placenta implants in the lower part of the uterus, partly or completely obstructing the cervical outlet to the vagina (birth canal).
Review Date: 5/16/2016
Reviewed By: Irina Burd, MD, PhD, Associate Professor of Gynecology and Obstetrics at Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.