title: Quantifying risks of preterm birth in the Arkansas Medicaid population, 2001-2005.
abstract: OBJECTIVE
  The objective of this study was to examine risks of preterm births, quantify the explanatory power achieved by adding medical and obstetric risk factors to the models and to examine temporal changes in preterm birth due to changes in Medicaid eligibility and the establishment of a maternal-fetal medicine referral system.
  
  
  METHODS
  The study used data from the 2001 to 2005-linked Arkansas (AR) Medicaid claims and birth certificates of preterm and term singleton deliveries (N=89 459). Logistic regression modeled the association among gestational age, demographic characteristics and risk factors, pooled and separately by year.
  
  
  RESULTS
  Physiological risk factors were additive with demographic factors and explained more of the preterm birth ≤32 weeks than later preterm birth. Changing eligibility requirements for Medicaid recipients and increasing the financial threshold from 133 to 200% of federal poverty level had an impact on temporal changes. The proportion of births ≤32 weeks declined to 33%, from 3.0 to 2.0. However, later preterm births declined and then increased in the last year.
  
  
  CONCLUSIONS
  Physiological conditions are strongly associated with early preterm birth. Maternal behaviors and other stressors are predictive of later preterm birth. Unmeasured effects of poverty continue to have a role in preterm birth. Further examination of the referral system is needed.
authors.affiliation: Department of Health Care Organization and Policy, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA. mslay@uab.edu
authors.forename: M S
authors.initials: MS
authors.lastname: Wingate
authors.forename: J
authors.initials: J
authors.lastname: Bronstein
authors.forename: R W
authors.initials: RW
authors.lastname: Hall
authors.forename: R R
authors.initials: RR
authors.lastname: Nugent
authors.forename: C L
authors.initials: CL
authors.lastname: Lowery
mesh_terms: D000293:Adolescent; D001131:Arkansas / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D015438:Health Behavior; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D008484:Medicaid; D015999:Multivariate Analysis; D007752:Obstetric Labor, Premature / Q000453:epidemiology* / Q000208:ethnology; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000208:ethnology / Q000209:etiology; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States; D055815:Young Adult