Adequate use and early initiation of prenatal care in the United States increased among both black and white women between 1981 and 1998.¹ The proportion of women with adequate use of prenatal care steadily increased from 34% to 50% among whites and from 27% to 44% among blacks, while the proportion initiating care within the first trimester increased from 80% to 85% among whites and from 61% to 73% among blacks. Intensive use of services, as measured by two standard indices, also rose. Overall, racial disparities in prenatal care decreased during the study period, with the exception of certain measures among high-risk groups, such as young and unmarried mothers.

To examine the trends and racial disparities in use of prenatal care among U.S. women, researchers gathered information from the natality files of the National Center for Health Statistics. They analyzed all available birth certificate data for live singleton infants born to white and black women in the 50 states and the District of Columbia from 1981 to 1998.

Data on the trimester in which prenatal care began and the Revised Graduated Index of Prenatal Care Utilization (R-GINDEX) and Adequacy of Prenatal Care Utilization Index (APNCU) were examined. The two indices classify prenatal care on the basis of the month that care began and the number of visits, adjusted for gestational age. For their study, the researchers looked at the R-GINDEX categories of intensive care (signifying approximately one standard deviation above the mean number of visits) and adequate care, and the APNCU category of intensive or adequate-plus care (signifying 110% of the number of visits recommended by the American College of Obstetricians and Gynecologists).

The researchers examined trends and percentage changes in the early initiation and use of prenatal care among the total population and among three social and demographic groups considered to be at high risk of adverse pregnancy outcomes: women with fewer than 12 years of education, women younger than 18 and unmarried women. Data were grouped into two-year increments. To assess changes in racial disparities among the total population and among the three high-risk groups, the researchers calculated the white-black ratio for each prenatal care measure for 1985-1987 and 1995-1997; a ratio of 1.00 signifies racial equity for that measure.

Overall, whites were more advantaged than blacks in regard to prenatal care, although utilization of services improved for both races over the study period. Between 1981-1982 and 1997-1998, the proportion of women with adequate use of prenatal care steadily increased among both whites (from 34% to 50%) and blacks (from 27% to 44%). An upward trend was also seen in the proportions of women of both races initiating prenatal care in the first trimester: from 80% to 85% among whites, and from 61% to 73% among blacks. Furthermore, intensive use of prenatal care increased among both white (R-GINDEX, from 18% to 30%; APNCU, from 3% to 7%) and black women (R-GINDEX, from 20% to 31%; APNCU, from 4% to 7%).

The racial gap in adequate use of prenatal care narrowed during the study period, with blacks making more substantial gains than whites (64% and 49%, respectively); the white-black ratio decreased from 1.25 to 1.14. A similar trend was seen in early initiation of care: The proportion of women starting prenatal care in the first trimester increased 19% among blacks and 6% among whites between 1981-1982 and 1997-1998; the white-black ratio decreased from 1.31 to 1.16. White women had greater gains than black women in intensive use of prenatal care as measured by both the APNCU (68% vs. 56%) and the R-GINDEX (94% vs. 91%), closing the gap in that measure as well; the white-black ratio rose from 0.90 to 0.96 for the APNCU and from 0.95 to 0.96 for the R-GINDEX.

During the study period, there were substantial changes in the proportions of births to women classified as being at high risk for adverse pregnancy outcomes. While the proportion that were to young women was essentially stable among white mothers (4%), it declined notably among blacks (from 12% to 10%). The proportion of births to mothers with fewer than 12 years of education decreased among blacks (from 35% to 27%) but increased among whites (from 19% to 21%); the proportion to unmarried mothers increased somewhat for blacks (from 57% to 69%) and more than doubled for whites (from 11% to 26%) between 1981-1982 and 1997-1998.

Among the high-risk groups studied, the overall trend was toward decreasing racial inequities in prenatal care initiation and use. However, there were some exceptions: Among young mothers, changes in the white-black ratio for adequate prenatal care (from 1.07 to 1.13) and for R-GINDEX intensive care (from 1.02 to 1.07) suggest that the racial disparities for those measures increased during the study period. Furthermore, the change in the ratio for early initiation of care among unmarried mothers (from 0.99 to 1.07) suggests a reversal in disadvantage from white to black women. There was no change in the ratio for R-GINDEX intensive care among women with low educational level (1.07).

The researchers comment that although it is encouraging to see the narrowing of racial disparities in early and adequate prenatal care, the reasons behind the changes are still unknown. They speculate that "national policy emphasis on and commitment to the reduction of racial disparities in health outcomes" and "efforts to promote more culturally competent care" may each be partially responsible. And they suggest that more work needs to be done to "assess the extent to which disparities exist for other racial, ethnic, and high-risk groups."--J. Rosenberg

REFERENCE

1. Alexander GR, Kogan MD and Nabukera S, Racial differences in prenatal care use in the United States: are disparities decreasing? American Journal of Public Health, 2002, 92(12):1970-1975.