Prenatal Care: The Kessner Index

Prenatal care programs are considered key interventions for increasing the likelihood of healthy outcomes for pregnant women and their babies. While prenatal care programs can take many forms, common to all are medical visits at recommended intervals as a means of catching problems that can threaten the pregnancy and the health of the mother.

These medical visits are captured in the Michigan Department of Health and Human Services (MDHHS) database, a database that tracks and reports extensive natality measures drawn from the birth certificate at the state, county, and place levels. Included among the measures is a rating of the adequacy of prenatal care. This rating, the Kessner Index, “…is a classification of prenatal care based on the month of pregnancy in which prenatal care began, the number of prenatal visits and the length of pregnancy (i.e., for shorter pregnancies, fewer prenatal visits constitute adequate care.)” The Appendix defines the three levels of adequacy of care — Adequate, Intermediate, and Inadequate — in more detail at the end of this blog post.

Objectives of the study

In this first blog post, we investigate differences among four areas of Southeast Michigan: Detroit, Wayne County outside of Detroit (Out-Wayne County), Oakland County, and Macomb County in the measure of the adequacy of prenatal care. A second blog post will investigate how prenatal care access differs by the mother’s age, educational attainment, and race in each of the four areas. Those analyses will help identify groups for which an intervention would have the largest potential to increase the adequacy of prenatal care. By conducting the analyses separately within the four areas, the findings will also address the issue of how place interacts with age, education, and in particular race in their effects on prenatal care. Both blog posts examine changes in prenatal care over the six-year period from 2017 to 2022.

Area Analyses

Adequate prenatal care

Figure 1, a graphic display of the data in Table 1, reveals that just half of Detroit women giving birth in 2017 had adequate prenatal care. This percentage remained steady until it started to edge up in 2020, eventually reaching 63%. The percentage of adequate prenatal care hovered around 70% for women in both Out-Wayne County and Macomb County from 2017-2019. It rose a bit in 2020 and 2021 for Macomb County. Oakland County held steady at around 80% adequacy all six years.

Figure 1.

Intermediate prenatal care

Detroit had the highest percentage of intermediate prenatal care at about 30% of the births during the six years. Given that the level of adequate prenatal care for Detroit women (Figure 1) increased from 2020 to 2022 and intermediate care remained relatively steady, inadequate care must have fallen for Detroit women, as Figure 3 and Table 3 below demonstrate.

Figure 2.

Two of the areas – Detroit and Macomb County exhibited impressive reductions in inadequate prenatal care. Detroit cut its rate of inadequate care from 21% in 2017 to 12% in 2022, while Macomb County reduced its rate from about one-eighth in 2017 to 4% in 2022, equal to the 2022 rate in Oakland County.

Figure 3.

Discussion

In this first blog post we introduced the concept and measurement of prenatal care in four areas of southeast Michigan. Comparing levels of care (adequate, intermediate, and inadequate) in Detroit, Out-Wayne County, Oakland County, and Macomb County over the six years from 2017-2022 we found that Detroit had the lowest level of adequate prenatal care during the earliest years but also showed the largest improvements. Out-Wayne County and Macomb County had roughly equal levels at around 70% of adequate care. Oakland County at around 80% ranked highest.

This analysis was at very high levels – the county and a major city. There are no clear, unambiguous reasons why we should find the differences and some similarities among areas that we did find. We need to dig deeper, for example by focusing on smaller geographic areas or, as we have chosen to do in a second blog post, by characteristics of the mothers giving birth. In a second blog post we will examine differences in adequacy by age of the mother, race, and educational attainment. This can help practitioners target those groups with the greatest potential for improvement.

In addition we will be able to examine the interaction between a characteristic and place of residence. For example, we can ask whether the effect on adequacy of prenatal care for teenagers is the same in Detroit as it is in Out-Wayne County or Oakland County. This analysis can supplement an earlier examination of the effects of race and place on low birthweight babies in the same four geographic areas as in this report.

Appendix

Kessner Index Measurement Definitions:

Adequate: Care that began within the first trimester and included an average of at least one or two additional prenatal visits per month of gestation, depending on the length of gestation.

Intermediate: Care that began during the second trimester of pregnancy with correspondingly fewer visits, or began during the first trimester but with fewer visits than would be appropriate for the length of gestation.

Inadequate: When no care was received or if care began during the third trimester. It is also inadequate if care began during the first or second trimester but less than five visits occurred, when the length of gestation was 34 weeks or more. When the length of gestation was less than 34 weeks, care is defined as inadequate when care began during the first or second trimester but a number of visits less than four occurred, that number depending on the actual weeks of gestation.

Source: 2022 Geocoded Michigan Birth Certificate Registry.
Division for Vital Records & Health Statistics, Michigan Department of Health & Human Services

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