title: Comparison of maternal risk factors between placental abruption and placenta previa.
abstract: The purpose of this study was to compare risk factors between placental abruption and placenta previa among primiparous and multiparous singleton pregnancies. We analyzed data from a population-based retrospective cohort with singleton pregnancies in the United States for 1995 to 2000. Maternal risk factors for placenta previa and placental abruption were examined using multiple logistic regressions. A total of 5,630,854 primiparous and 11,026,768 multiparous singleton pregnancies were available for final analyses after excluding subjects with missing information on outcomes or important exposures. Placental abruption was recorded in 4.8 per 1000 primiparous singleton births and 5.9 per 1000 multiparous singleton pregnancies. The occurrence of placenta previa was 1.9 per 1000 primiparous singleton pregnancies and 3.9 per 1000 multiparous singleton pregnancies. The effects of maternal age, race, parity, and previous cesarean section were stronger on placenta previa than on placental abruption, and the effects of cigarette smoking, alcohol drinking, and prenatal care were stronger on placental abruption than on placenta previa. A composite outcome of selected medical and pregnancy complications was related with placental abruption but not with placental previa. Placental abruption is more likely to be affected by conditions occurring during pregnancy, and placenta previa is more likely to be affected by conditions existing prior to pregnancy.
authors.affiliation: OMNI Research Group, Clinical Epidemiology Program, Ottawa Health Research Institute, University of Ottawa, Ontario, Canada. qyang@ohri.ca
authors.forename: Qiuying
authors.initials: Q
authors.lastname: Yang
authors.forename: Shi Wu
authors.initials: SW
authors.lastname: Wen
authors.forename: Karen
authors.initials: K
authors.lastname: Phillips
authors.forename: Lawrence
authors.initials: L
authors.lastname: Oppenheimer
authors.forename: Douglas
authors.initials: D
authors.lastname: Black
authors.forename: Mark C
authors.initials: MC
authors.lastname: Walker
mesh_terms: D000037:Abruptio Placentae / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects; D001294:Attitude to Health; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D008423:Maternal Age; D008429:Maternal Welfare; D015999:Multivariate Analysis; D010298:Parity; D010923:Placenta Previa / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000209:etiology; D011256:Pregnancy Outcome; D011295:Prenatal Care; D011336:Probability; D012189:Retrospective Studies; D018570:Risk Assessment; D012309:Risk-Taking; D012680:Sensitivity and Specificity; D012907:Smoking / Q000009:adverse effects; D014481:United States / Q000453:epidemiology; D055815:Young Adult