title: Risk factors for preterm delivery with placenta previa.
abstract: OBJECTIVE
  To identify factors associated with preterm delivery in cases of sonographically identified placenta previa.
  
  
  METHODS
  Pregnancies with sonographic evidence of placenta previa at ≥ 28 weeks were identified. Demographic information, antepartum course, and delivery information were extracted from electronic medical records. Statistical analysis was performed with Fisher's exact test, Mann-Whitney U, Spearman's ρ (correlation), and logistic regression. Continuous data are presented as median (interquartile range).
  
  
  RESULTS
  Of 113 singleton pregnancies with placenta previa, 54 (48%) delivered at term and 59 (52%) delivered preterm. Fifty-one (45%) experienced antepartum bleeding at a median gestational age of 31 weeks (29-33 weeks) with a median interval of 20 days (11-33 days) between first bleeding episode and delivery. Women with antepartum bleeding were more likely to be delivered for hemorrhage (36 of 51 vs. 8 of 62, P<0.001) and delivered emergently (40 of 51 vs. 14 of 62, P<0.001). Antepartum bleeding before 34 weeks had a positive predictive value of 88% for preterm birth and 83% for emergent delivery.
  
  
  CONCLUSIONS
  In pregnancies with placenta previa, antepartum bleeding is a strong predictor of preterm delivery.
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, New York, NY, USA. sgf2001@med.cornell.edu
authors.forename: Shira G
authors.initials: SG
authors.lastname: Fishman
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chasen
authors.forename: Bani
authors.initials: B
authors.lastname: Maheshwari
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D009519:New York City / Q000453:epidemiology; D010923:Placenta Previa / Q000453:epidemiology*; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014592:Uterine Hemorrhage / Q000453:epidemiology