Initial Findings in Infant Mortality from the Birth Certificate & Medicaid Data Match Project

Minnesota Department of Health & Department of Human Services

Fall 2005

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Background

Infant mortality is defined as death to a live born infant occurring within the first year of life and is expressed as a rate of deaths per 1,000 live births. This fact sheet uses linked birth and death data for all infant mortality rates to compare Medicaid and non-Medicaid populations.

Infant mortality is an important indicator to compare the health and well-being of populations among and within countries and states. Between 1950 and 2001, the U.S. infant mortality rate declined 77% from 30 deaths per 1,000 live births to 6.8 deaths per 1,000 live births. In 2002, the U.S. rate rose for the first time in over 40 years to 7.0 per 1,000 live births. The U.S. ranks 27th in infant mortality among developed countries.

Minnesota’s infant mortality rate for 2002 was 5.3 per 1,000 live births, fourth lowest among states that year, and has always been lower than the overall national rate. But this relatively low state rate masks disparities among Minnesota’s racial and ethnic populations, infants born to teens, and infants born to poor or low-income mothers

Purpose

This fact sheet highlights differences in rates of infant deaths, causes of deaths, and rates of initiation of prenatal care among populations defined by race/ethnicity, age, and Medicaid status.

Methods

The Minnesota Department of Health (MDH) and the Minnesota Department of Human Services (DHS) used an iterative process to link all birth and infant death certificates to Medicaid enrollment data for Minnesota for calendar years 1997-2001. Using population birth and infant death data, secondary data analysis on a variety of sociodemographic and pregnancy-related indicators was conducted on two populations—Medicaid and non-Medicaid. In this study Medicaid births included those covered by the Medical Assistance and MinnesotaCare Programs. Non-Medicaid included births to women who were covered by private health insurance, were self-insured or were uninsured. The non-Medicaid population also includes an indeterminate number of poor or low-income and uninsured women. The study used Medicaid status is a proxy indicator for poverty or low-income.

Findings

Overall, infant mortality rates were 7.4 deaths per 1,000 live births for Medicaid compared to 5.2 deaths per 1,000 live births for non-Medicaid.

From 1997-2001 in Minnesota, the rate of births to women ages 15-19 among the Medicaid population was four times higher than the rate for non-Medicaid women in that age group. For ages 20-24 the birth rate was almost three times higher among Medicaid women. For women over age 35, the birth rate was almost three times higher in the non-Medicaid group than for Medicaid women of that age.

Table 1 depicts infant mortality rates for the Medicaid and non-Medicaid populations by race/ethnicity:

Table 1: Infant Mortality Rates by Race & Ethnicity & Medicaid Status, Minnesota 1997-2001
  Rate per 1,000 Births
Race & Ethnicity Medicaid Non-Medicaid
White
6.4
4.7
African American
10.8
14.3
American Indian
11.0
13.8
Asian/PI
6.6
7.0
Hispanic*
5.8
8.6
Overall
7.4
5.2
*Hispanic ethnicity may include any race.

Overall, whites had significantly lower infant mortality rates than all other race categories irrespective of Medicaid status. Non-Medicaid whites had significantly lower infant mortality rates than Medicaid whites. In contrast, African Americans, American Indians, Asians, and Hispanics all had lower infant mortality rates among the Medicaid women, although the difference for Asians was minimal.

Table 2 depicts infant mortality rates for the Medicaid and Non-Medicaid populations by age of mother:

Table 2: Infant Mortality Rates by Medicaid Status and Age of Mother, Minnesota 1997-2001
  Rates per 1,000 Births
Age Medicaid Non-Medicaid
< 20 years
7.8
11.5
20 to 35 years
7.1
4.7
> 35 years
10.5
6.2

Teens on Medicaid had lower rates of infant death than non-Medicaid teens. But for women 20 or above, non-Medicaid women had a lower rate of infant deaths.

Table 3 depicts infant mortality rates by initiation of prenatal care:

Table 3: Infant Mortality Rates by Prenatal Care by Trimester and Medicaid Status, Minnesota 1997-2001
  Rates per 1,000 Births
Trimester Medicaid Non-Medicaid
1st Trimester
6.8
4.5
2nd Trimester
7.3
6.7
3rd Trimester or No Care
12.4
13.2

Women with early initiation of prenatal care had lower infant death rates for both Medicaid and non-Medicaid populations.

Table 4 depicts the top six causes of deaths:

Table 4: Percent of Deaths by Cause and Medicaid Status, Minnesota 1997-2001
  Percent
Cause of Death Non-Medicaid Medicaid
Congenital Anomalies
32.5
23.5
SIDS
6.0
15.1
Disorders Relating to Prematurity
12.5
9.4
Unintentional Injury
2.8
6.2
Maternal Complications
6.4
4.9
Placenta or Cord Complications
4.8
4.2

The proportion of deaths due to Sudden Infant Death Syndrome (SIDS) was 2.5 times higher in the Medicaid than in the non-Medicaid population. Among Medicaid births, unintentional injury accounted for a higher proportion of infant deaths as compared to non-Medicaid. Notably, among Medicaid deaths one in three unintentional injury deaths was related to an infant co-sleeping with adults or in other unsafe infant sleep arrangements.

Data Limitations:

Small numbers of infant deaths, especially in populations of color and American Indians, make infant mortality rates susceptible to random variation. The Medicaid population may have been uninsured during some or all of the pregnancy; enrollment time factors are undetermined in this study.

Conclusions

This study demonstrated differences in infant mortality rates between Medicaid and non-Medicaid populations. Overall infant mortality was higher in the Medicaid population than in non-Medicaid. Though not always statistically significant, women of color and American Indian women had lower rates of infant death when covered by Medicaid than those in the non-Medicaid population. It was also true that teen mothers covered by Medicaid had lower infant death rates than teens in the non-Medicaid population.

Among the causes of death, Medicaid-covered women had lower proportions of infant deaths due to congenital anomalies (birth defects), prematurity, maternal complications, and placenta or cord complications as compared to non-Medicaid women. Medicaid-covered women, however, had higher proportions of infant deaths from unintentional injuries and SIDS as compared to non-Medicaid women.

Further research is needed to examine the overall higher infant mortality rates among Medicaid-covered women as compared to non-Medicaid women. Additionally, further research is needed to explain the lower infant death rates among teens, women of color, and American Indians enrolled in Medicaid during pregnancy and birth.

For the complete report and references, see The Birth Certificate and Medicaid Data Match Project: Initial Findings in Infant Mortality, March 2005.

 

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