title: [A retrospective analysis on the pernicious placenta previa from 2008 to 2014].
abstract: OBJECTIVE
  To investigate the incidence changes, clinical characteristics and pregnant outcomes of pernicious placenta previa.
  
  
  METHODS
  A retrospective cohort analysis on 316 cases with placenta previa in the Peking University First Hospital from January 2008 to December 2014. The research group were 60 cases with the patients of placenta previa with the history of cesarean section, and the control group were placenta previa without the history of cesarean section. Compared with the incidence, intraoperative blood loss, the pregnancy outcomes and so on.
  
  
  RESULTS
  (1) The average incidence rate of placenta previa during the past 7 years was 10.96 ‰ (316/28 837). And the cases of pernicious placenta previa was 60 (2.08‰, 60/28 837), the incidence of pernicious placenta previa was rising from 2008 to 2014 (0.91‰-3.08‰). (2) There were 145 cases of placenta privia had been translation from other hospitals in the past 7 years. The referral rate of pregnant women with placenta previa was 45.9% (145/316), and the referral rate of pernicious placenta previa (63.3%, 38/60) was significantly higher than that of non-pernicious placenta previa group (41.8%, 107/256; χ(2)=9.080, P=0.003). Referral the outcomes of these patients were good, and no maternal death occurred. (3) The placenta in the research group were mainly adhered in the front wall of the uterine, and the incidence was 38.5% (15/39), higher than that in the group of non-pernicious placenta previa (12.1%, 21/174; χ(2)=57.636, P<0.01). The incidence rate of complicated placenta increased in research group was 53.3% (32/60), higher than that in the group of non-pernicious placenta previa, compared with the control group, there was significant difference (15.6%, 40/256; χ(2)= 39.041, P<0.01). (4) The incidence of blood loss was more than 1 000 ml, blood transfusion rate, the rate of hysterectomy and the rate of asphyxia of newborn in the research group were respectively 41.7% (25/60), 38.3% (23/60), 8.3% (5/60), 15.0% (9/60), and the incidence of the group of non-pernicious placenta previa were respectively 4.7% (12/256), 12.9% (33/256), 1.2% (3/256), 8.6% (22/256), compared those in other two groups, there were not significant difference (P<0.05).
  
  
  CONCLUSIONS
  The incidence rate of placenta previa increased year by year, patients with placenta previa has a history of cesarean section often combined with placenta in anterior wall of the uterus, and often with poor pregnancy outcomes. Hierarchical referral system is an effective means to reduce the mortality of the pernicious placenta previa.
authors.affiliation: Department of Obstetrics and Gynecology, Perking University First Hospital, Beijing 100034, China.
authors.forename: L
authors.initials: L
authors.lastname: Yu
authors.forename: K J
authors.initials: KJ
authors.lastname: Hu
authors.forename: H X
authors.initials: HX
authors.lastname: Yang
mesh_terms: D016063:Blood Loss, Surgical; D001803:Blood Transfusion; D002585:Cesarean Section; D005260:Female; D006801:Humans; D007044:Hysterectomy; D015994:Incidence; D007231:Infant, Newborn; D010923:Placenta Previa / Q000453:epidemiology* / Q000473:pathology; D006473:Postpartum Hemorrhage / Q000453:epidemiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D012307:Risk Factors; D014599:Uterus