Pregnancy and birth outcome improvements for American Indians in the Healthy Start project of the Inter-Tribal Council of Michigan, 1998-2008.

American Indians living in Michigan experience disproportionately high rates of infant mortality. This 11-year (1998-2008) cohort study evaluated impacts of a Healthy Start (HS) program administered by the Inter-Tribal Council of Michigan (ITCM) on perinatal outcomes. Women who enrolled in ITCM's HS program ("exposed") were compared with non-enrolled ("unexposed") for four outcomes: low birth weight (LBW), small for gestational age, preterm birth, and inadequate prenatal care. To classify exposed and unexposed women and their children, Michigan vital records data were linked with HS enrollment records to identify participants and non-participants among all American Indian births. Logistic regression was used to calculate odds ratios for the four outcomes of interest. Analyses were stratified for high and low access to care based on Medically Underserved Area (MUA) designation for a woman's county of residence. Of 4,149 American Indian births during the period, 872 were to women who enrolled prenatally in HS. Although unstratified analysis showed no differences between HS participants and non-participants, stratified analyses demonstrated that participants from MUA counties had decreased odds of LBW and inadequate prenatal care. Results suggest that in MUA counties where participants and non-participants are at similar risk for poor outcomes, HS may be reducing barriers and improving outcomes. In non-MUA counties participants had similar outcomes as non-participants. These results may reflect a wider disparity in risk factors between the two groups in non-MUA counties. The complex interplay among need, access, and benefit complicates analyses and suggests the importance of more in-depth and focused studies.