title: Proceedings: Placental localization by sonar--a safe procedure.
mesh_terms: D000649:Amniocentesis; D005260:Female; D006801:Humans; D010920:Placenta; D010923:Placenta Previa / Q000175:diagnosis; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000175:diagnosis; D014463:Ultrasonography