title: Maternal ABO blood group and stillbirth: a prospective cohort investigation.
abstract: OBJECTIVE
  To determine whether maternal ABO blood group is associated with risk of stillbirth.
  
  
  METHODS
  Prospective cohort. Risk of stillbirth among women of blood group A, B and AB was compared to that of women with group O by logistic regression and survival analysis.
  
  
  RESULTS
  There were 1,018 stillbirths in 52,605 pregnancies (19.4 per thousand). Stillbirths occurred in 19.2/ 1,000 pregnancies in group O, 19.8/1,000 pregnancies in group A (race-adjusted odds ratio [OR] vs. group O of 1.1, 95% confidence interval [CI] 0.9-1.2), 19.4/1,000 to group B (race-adjusted OR vs. group O of 1.0, 95% CI 0.8-1.2), and 17.2/1,000 pregnancies in group AB (race-adjusted OR vs. group O of 0.9, 95% CI 0.6-1.2) women. Survival analysis, accounting for varying times at entry to prenatal care, produced similar results. Results were similar for singleton births, stillbirths < 24 weeks' and > or = 24 weeks' gestation, and antepartum and intrapartum stillbirths considered separately.
  
  
  CONCLUSIONS
  Maternal ABO blood group was not associated with stillbirth.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Klebanoff
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Lynch
mesh_terms: D000017:ABO Blood-Group System; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D050497:Stillbirth / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000017:ABO Blood-Group System