title: Ultrasound-detected subchorionic hemorrhage and the obstetric implications.
abstract: OBJECTIVE
  To estimate the association between the ultrasonographic diagnosis of subchorionic hemorrhage and adverse pregnancy outcomes.
  
  
  METHODS
  This was a retrospective cohort study of all consecutive women undergoing routine ultrasonography before 22 weeks with a singleton gestation at one institution from 1994 to 2008. Presence or absence of subchorionic hemorrhage defined the two study groups. The primary outcomes were abruption, intrauterine growth restriction defined as birth weight less than the 10th percentile, and nonanomalous intrauterine fetal demise after 20 weeks. Secondary outcomes included preeclampsia, preterm premature rupture of membranes, and preterm delivery before 37 weeks and before 34 weeks of gestation. Univariable, bivariate, and multiple logistic regression analyses were performed.
  
  
  RESULTS
  Of the 63,966 women in the patient population, 1,081 had subchorionic hemorrhage (1.7%). Women with a subchorionic hemorrhage were at increased risk of abruption (n=432, 3.6% compared with 0.6%, adjusted odds ratio 2.6, 95% confidence interval 1.8-3.7) and of preterm delivery (n=6,601, 15.5% compared with 10.5%, adjusted odds ratio 1.3, 95% confidence interval 1.1-1.5), even after adjusting for bleeding during pregnancy, chronic hypertension, body mass index, race, diabetes mellitus, tobacco use, and previous preterm delivery.
  
  
  CONCLUSIONS
  Women with ultrasound-detected subchorionic hemorrhage before 22 weeks of gestation are at increased risk of placental abruption and preterm delivery but are not at increased risk of other adverse pregnancy outcomes.
  
  
  METHODS
  II.
authors.affiliation: From Department of Obstetrics and Gynecology, Washington University, St. Louis, Missouri.
authors.forename: Shayna M
authors.initials: SM
authors.lastname: Norman
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Odibo
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Dicke
authors.forename: James P
authors.initials: JP
authors.lastname: Crane
authors.forename: Alison G
authors.initials: AG
authors.lastname: Cahill
mesh_terms: D000037:Abruptio Placentae / Q000209:etiology; D000328:Adult; D002823:Chorion / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D006470:Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D010922:Placenta Diseases / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D014463:Ultrasonography