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: 2/19/2008
Reviewed By: Peter Chen, MD, Department of Obstetrics & Gynecology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.