title: Maternal-fetal medicine specialist density is inversely associated with maternal mortality ratios.
abstract: OBJECTIVE
  Our study's objective was to determine the relationship between state-specific maternal mortality ratios and the density of maternal-fetal medicine specialists.
  
  
  METHODS
  State maternal mortality ratios from 1994 to 2001 were calculated from the Centers for Disease Control and Prevention WONDER database. Practitioner distribution data were obtained from professional associations. Demographic information regarding states was gathered from the 2000 US census data. Bivariable and multivariable analyses were conducted with the use of Spearman correlations and Poisson regression, respectively.
  
  
  RESULTS
  The median state maternal-mortality ratio was 7.5/100,000 live births. Our study showed that an increase of 5 maternal-fetal specialists per 10,000 live births results in a 27% reduction in the risk of maternal death (relative risk [RR] = 0.73, 95% CI = 0.58-0.93, P = 0.012). This risk reduction was based on a multivariable Poisson regression model that included the following variables and their significant interactions: state-specific percentages of mothers in poverty, mothers without a high school diploma, minority mothers, and teenage mothers.
  
  
  CONCLUSIONS
  The density of maternal-fetal medicine specialists is significantly and inversely associated with maternal mortality ratios, even after controlling for state-level measures of maternal poverty, education, race, age, and their significant interactions.
authors.affiliation: Department of Obstetrics/Gynecology, Medical University of South Carolina, Charleston, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Sullivan
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Hill
authors.forename: Roger B
authors.initials: RB
authors.lastname: Newman
authors.forename: M Kathryn
authors.initials: MK
authors.lastname: Menard
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008428:Maternal Mortality; D009774:Obstetrics; D010820:Physicians / Q000600:supply & distribution*; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D000078329:Workforce