title: Maternal morbidity associated with placenta praevia among women who had elective caesarean section.
abstract: OBJECTIVE
  Estimates of the increased risk of maternal complications after caesarean section posed by placenta praevia differ between studies and may not reflect current practice. We assess the impact of placenta praevia on maternal complications after elective caesarean section (CS).
  
  
  METHODS
  We undertook a retrospective cohort study of women who had an elective CS for a singleton at term in the English National Health Service between 1 April 2000 and 28 February 2009 using routine data from the Hospital Episode Statistics database. Multiple logistic regression was used to estimate the effect of placenta praevia on maternal complications after controlling for maternal age, parity, whether a woman had a previous CS, and gestational age. Maternal complications included postpartum haemorrhage, obstetric trauma, blood transfusion and hysterectomy.
  
  
  RESULTS
  Among 131,731 women having an elective CS for a singleton, 4,332 (3.3%) women had placenta praevia. Placenta praevia increased the risk of postpartum haemorrhage from 9.7% to 17.5% (adjusted odds ratio (OR) 1.91; 95% CI: 1.74 to 2.09), the risk of blood transfusion from 1.4% to 6.4% (OR 4.39; 3.76 to 5.12), and the risk of hysterectomy from 0.03% to 1% (OR 39.70; 22.42 to 70.30). Previous studies have estimated the rate of hysterectomy among women with placenta praevia to be 5%.
  
  
  CONCLUSIONS
  Placenta praevia remains a risk factor for various maternal complications, although the increased risk of hysterectomy is lower than previously reported.
authors.affiliation: Office for Clinical Research and Audit, Royal College of Obstetricians and Gynaecologists, London, UK.
authors.forename: Chidimma
authors.initials: C
authors.lastname: Onwere
authors.forename: Ipek
authors.initials: I
authors.lastname: Gurol-Urganci
authors.forename: David A
authors.initials: DA
authors.lastname: Cromwell
authors.forename: Tahir A
authors.initials: TA
authors.lastname: Mahmood
authors.forename: Allan
authors.initials: A
authors.lastname: Templeton
authors.forename: Jan H
authors.initials: JH
authors.lastname: van der Meulen
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion / Q000706:statistics & numerical data; D002585:Cesarean Section / Q000009:adverse effects*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007044:Hysterectomy / Q000706:statistics & numerical data; D015994:Incidence; D009017:Morbidity; D010923:Placenta Previa / Q000453:epidemiology* / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery; D006473:Postpartum Hemorrhage / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D013222:State Medicine; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult