title: Birth outcomes among low-income women- documented and undocumented.
abstract: BACKGROUND
  In January 2007, Texas expanded the Children's Health Insurance Program (CHIP) to include perinatal care for the unborn children of undocumented low-income women and certain documented women ineligible for Medicaid or CHIP because of income or residency status. CHIP Perinatal includes coverage for undocumented women and provides a glimpse into the birth outcomes of this difficult-to-reach population.
  
  
  OBJECTIVE
  Community Health Choice (CHC) is the largest health maintenance organization provider of CHIP Perinatal in Texas, and we sought to determine preterm and low-birth-weight rates among women enrolled in CHC CHIP Perinatal and compare them with women of similar low-income status enrolled in Medicaid.
  
  
  METHODS
  We conducted a retrospective cohort study of women enrolled in the CHC CHIP Perinatal and Medicaid plans and who delivered between January 1 and August 31, 2008. Logistic regression was used to determine odds of poor birth outcome, and analyses were adjusted for maternal age.
  
  
  RESULTS
  The CHC cohort included 10,763 pregnant women enrolled in CHIP Perinatal and 4614 pregnant women enrolled in Medicaid. Those in the Medicaid group are significantly more likely to have preterm (adjusted odds ratio [aOR] = 2.1; 95% confidence interval [CI], 1.8-2.4) and low-birth-weight infants (aOR = 2.2; 95% CI, 1.9-2.6) than those in the CHIP Perinatal group. Within the Medicaid population, Hispanic women have the lowest preterm and low-birth-weight rates (6.6% and 5.8%, respectively), and non-Hispanic black women have the highest preterm and low-birth-weight rates (11.3% and 12.4%, respectively). However, Hispanic women enrolled in Medicaid are more likely to have preterm (aOR = 1.7; 95% CI, 1.4-2.1) and low-birth-weight infants (aOR = 1.6; 95% CI ,1.3-2.0) than their mostly Hispanic CHIP Perinatal counterparts.
  
  
  CONCLUSIONS
  Women enrolled in CHC CHIP Perinatal have significantly lower prematurity rates than women of similar economic status enrolled in Medicaid, despite receiving less comprehensive medical benefits. Favorable birth outcomes for the mostly Hispanic CHIP Perinatal population persist even when restricting the comparison Medicaid group to Hispanics. Further analysis controlling for factors such as social and behavioral characteristics is needed to better understand differences between the CHIP Perinatal and Medicaid populations.
authors.affiliation: Department of Family and Community Medicineat Baylor College of Medicine; Harris CountyHospital District in Houston, TX, USA. bndang@bcm.edu
authors.forename: Bich Ngoc
authors.initials: BN
authors.lastname: Dang
authors.forename: Louise
authors.initials: L
authors.lastname: Van Dessel
authors.forename: June
authors.initials: J
authors.lastname: Hanke
authors.forename: Margo A
authors.initials: MA
authors.lastname: Hilliard