title: Maternal age and placenta previa: a population-based, case-control study.
abstract: OBJECTIVE
  Our purpose was to determine if advanced maternal age has an adverse effect on placenta previa independent of other risk factors.
  
  
  METHODS
  A population-based, case-control study was performed with North Carolina vital records from 1988 to 1990, individually matching controls to cases on maternal race, gravidity, parity, previous spontaneous or induced abortion, previous cesarean section, and gestational age at delivery.
  
  
  RESULTS
  A multivariate analysis showed that women aged 34 years or older had a two to three times higher risk of placenta previa in relation to women < 20 years old. A clear dose-response pattern was observed with increasing age.
  
  
  CONCLUSIONS
  Advancing maternal age appears to increase the risk of placenta previa independent of other factors.
authors.affiliation: Carolina Population Center, University of North Carolina, Chapel Hill 27599-7400.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: D A
authors.initials: DA
authors.lastname: Savitz
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002585:Cesarean Section / Q000009:adverse effects; D005260:Female; D006801:Humans; D008423:Maternal Age; D015999:Multivariate Analysis; D010298:Parity; D010923:Placenta Previa / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D012307:Risk Factors