The effect of prenatal support on birth outcomes in an urban midwestern county.

OBJECTIVES In Dane County, Wisconsin, the black-white infant mortality gap started decreasing from 2000 and was eliminated from 2004 to 2007. Unfortunately, it has reappeared since 2008. This paper examines risk factors and levels of prenatal care to identify key contributors to the dramatic decline and recent increase in black infant mortality and extremely premature birth rates. METHODS This retrospective cohort study analyzed approximately 100,000 Dane County birth, fetal, and infant death records from 1990 to 2007. Levels of prenatal care received were categorized as "less-than-standard," "standard routine" or "intensive." US Census data analysis identified demographic and socioeconomic changes. Infant mortality rates and extremely premature ( < or = 28 weeks gestation) birth rates were main outcome measures. Contributions to improved outcomes were measured by calculating relative risk, risk difference and population attributable fraction (PAF). Mean income and food stamp use by race were analyzed as indicators of general socioeconomic changes suspected to be responsible for worsening outcomes since 2008. RESULTS Risk of extremely premature delivery for black women receiving standard routine care and intensive care decreased from 1990-2000 to 2001-2007 by 77.8% (95% CI = 49.9-90.1%) and 57.3% (95% CI = 27.6-74.8%) respectively. Women receiving less-than-standard care showed no significant improvement over time. Racial gaps in mean income and food stamp use narrowed 2002-2007 and widened since 2008. CONCLUSIONS Prenatal support played an important role in improving black birth outcomes and eliminating the Dane County black-white infant mortality gap. Increasing socioeconomic disparities with worsening US economy since 2008 likely contributed to the gap's reappearance.