title: [Value of transvaginal sonography in diagnosis of placenta previa].
abstract: OBJECTIVE
  To investigate the value of transvaginal sonography (TVS) in diagnosis of placenta previa.
  
  
  METHODS
  Transabdominal sonography(TAS) and TVS localization of the placenta were performed in 78 pregnant women after 35 week's gestation. It was suspected of having placenta previa when the placental edge appeared to be over or within 2 cm in diameter of the internal cervical os demonstrated by TAS or TVS. Final diagnosis depended on diagnosis at delivery. The diagnostic sensitivity, specificity, false-positive rate and coincidence rate were made in comparison between TVS and TAS.
  
  
  RESULTS
  The sensitivity, specificity, false-positive rate and coincidence rate of TVS were 100%, 90%, 10% and 93.6%, while that of TAS were 71.4%, 60%, 40% and 64.1%, respectively. The coincidence rate of TVS was better than TAS (p < 0.01).
  
  
  CONCLUSIONS
  TVS is superior to TAS in diagnosis of placenta previa.
authors.affiliation: Department of Ultrasonography, Second Xiangya Hospital, Central South University, Changsha 410011, China.
authors.forename: J M
authors.initials: JM
authors.lastname: Chen
authors.forename: Q C
authors.initials: QC
authors.lastname: Zhou
authors.forename: R R
authors.initials: RR
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D010923:Placenta Previa / Q000000981:diagnostic imaging*; D011247:Pregnancy; D014463:Ultrasonography; D014621:Vagina / Q000648:ultrastructure*