Prenatal care utilization in New York City: Comparison of measures and assessment of their significance for urban health

This paper considers policy and programmatic consequences of shifting measurements of prenatal care utilization from the Kessner Index (KI) to the Adequacy of Prenatal Care Utilization Index (APNCUI). In gauging in adequacy of prenatal care utilization, the KI considers the timing of prenatal care initiation and the number of prenatal visits. The APNCUI also considers both timing of initiation and number of visits, but the approach taken to conceptualizing and measuring these two aspects of prenatal care utilization is more refined. We used birth certificates to calculate the KI and APNCUI for 217,183 New York City (NYC) births in 1991-1992. We used cross-tabulations and bivariate odds ratios to compare the classifications resulting from the respective indexes. The APNCUI detected some important dimensions of the problem of inadequate prenatal care use that are not evident when using the KI. The proportion of births with inadequate use increases from 18% with the KI to 35% with the APNCUI. Groups of women at elevated risk for inadequate use are the same, but the KI understates significantly the risk for Hispanic women, teens, women who are less well educated, and those on WIC and Medicaid. The APNCUI yields a fuller picture of the degree to which some urban women are at risk for inadequate prenatal care use. Use of the APNCUI in quality assurance, monitoring, and research is recommended.