Infant Mortality by Marital Status of Mother -- United States, 1983
From 1950 to 1987, the proportion of out-of-wedlock births in the United States increased sixfold, from 4% (1) to 24% of all births, respectively. In 1987, 17% of live births among whites and 62% of live births among blacks were out of wedlock (2). Because out-of-wedlock childbearing is associated with adverse pregnancy and infant health outcomes, increasing attention has been focused on out-of-wedlock childbearing as a maternal and child-health policy issue in the United States.
In 1960, the infant mortality rates for out-of-wedlock births for whites and for all other races were 33.0 and 51.2 deaths per 1000 live births, respectively. Rates for all live births for whites and for all other races were 22.2 and 41.4 per 1000, respectively (3). To update these data, the 1983 national linked birth-death file (4) (the latest data available at the time of analysis) was analyzed; the analysis was restricted to singleton live births to U.S. resident white (n=2,875,283) and black (n=546,949) mothers.
In 1983, 13% of singleton live births among whites and 59% of singleton live births among blacks were to unmarried women. Twenty percent of infant deaths among whites and 66% of infant deaths among blacks were among infants born to unmarried mothers.
For both whites and blacks, unmarried motherhood was associated with an elevated overall infant mortality rate, but the association was greater for whites (rate ratio (RR)=1.7) than for blacks (RR=1.3) (Table 1). The overall infant mortality rate was higher for infants born to unmarried mothers (13.1 and 19.6 per 1000 live births for whites and blacks, respectively) than for infants born to married mothers (7.8 and 14.6 per 1000 live births for whites and blacks, respectively). However, infants born to unmarried mothers less than 18 years of age had slightly lower infant mortality rates (14.3 and 20.7 per 1000 for whites and blacks, respectively) than infants born to married mothers in this age group (15.4 per 1000 for whites and 23.4 per 1000 for blacks). For mothers greater than or equal to 18 years of age, the out-of-wedlock/in-wedlock mortality rate ratios were greater than 1 and generally increased with increasing maternal age.
The effect of marital status on infant mortality rates was greatest in the postneonatal period (28-364 days), where the variations in mortality by maternal age were larger. Postneonatal mortality for infants born to unmarried mothers was higher than for infants born to married women except for white mothers less than 18 years of age and black mothers less than 20 years of age. Reported by: T Bennett, DrPH, Institute for Health Policy Studies, Univ of California, San Francisco. Div of Analysis, National Center for Health Statistics; Div of Reproductive Health, Center for Chronic Disease Prevention and Health Promotion, CDC.
Editorial Note: Adverse pregnancy outcomes are correlated with poverty conditions. In 1988, 36% of black families and 12% of white families with children less than 18 years of age were classified as living in poverty. Families with unmarried mothers are even more likely to be living in poverty. In 1988, 56% of black families and 38% of white families with children less than 18 years of age and no male head of household were classified as living below the poverty level (5).
The finding in the 1983 birth cohort that infant mortality was lower in infants born to unmarried teenage mothers than in infants born to married teenagers is consistent with findings for earlier periods (6,7). This finding is not unexpected, since the marital status of the mother confers neither risk nor protection to the infant; rather, the principal benefits of marriage to infant survival are economic and social support.
The lack of economic and social support for married teenage mothers is a consequence of several factors. According to the 1980 U.S. Census, 39% of black married women aged 15-19 years were living separately from their husbands (8). Moreover, married teenagers are more likely to have unstable marriages than are older married persons (9) and are more likely to have repeated teenage childbearing than are unmarried teenagers (10). Married teenagers are also more likely to establish independent households, thereby estranging themselves from financial and child-care support from relatives (11).
The association between marital status and infant mortality rates is stronger in the postneonatal period than in the neonatal period. This association suggests that marital status is an important proxy measure of factors traditionally related to postneonatal mortality, such as socioeconomic status, social support, and other circumstances not reflected by education and other commonly used measures.
Washington, DC: US Department of Health, Education, and Welfare, Public Health Service, 1968; PHS publication no. (PHS)1677.
2. NCHS. Advance report of final natality statistics, 1987. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, 1989. (Monthly vital statistics report; vol 38, no. 3S).
3. Vavra HM, Querec LJ, NCHS. A study of infant mortality from linked records by age of mother, total-birth order, and other variables: United States, 1960 live-birth cohort. Rockville, Maryland: US Department of Health, Education, and Welfare, Public Health Service, 1973; DHEW publication no. (HRA)74-1851. (Vital and health statistics; series 20, no. 14).
4. NCHS. Linked birth/infant death data set: 1983 birth cohort. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, 1989.
5. Bureau of the Census. Money income and poverty in the United States 1988. Washington, DC: US Department of Commerce, Bureau of the Census, 1989. (Advance data from the 1989 Current Population Survey; series P60, no. 166).
6. NCHS. Infant mortality rates by legitimacy status: United States, 1964-66. Rockville, Maryland: US Department of Health, Education, and Welfare, Public Health Service, 1971; DHEW publication no. (HSM)72-1125. (Monthly vital statistics report; vol 20, no. 5S).
7. Berkov B, Sklar J. Does illegitimacy make a difference? A study of the life chances of illegitimate children in California. Population and Development Review 1976;2:201-17.
8. Bureau of the Census. 1980 Census of population. Vol 1. Characteristics of the population, detailed population characteristics: US summary, section B--regions. Washington, DC: US Department of Commerce, Bureau of the Census, 1989.
9. Baldwin W, Cain VS. The children of teenage parents. Fam Plann Perspect 1980;12:34-43. 10. Koenig MA, Zelnik M. Repeat pregnancies among metropolitan-area teenagers: 1971-1979. Fam Plann Perspect 1982;14:341-4. 11. Furstenberg FF Jr. Implicating the family: teenage parenthood and kinship involvement. In: Ooms T, ed. Teenage pregnancy in a family context: implications for policy. Philadelphia: Temple University Press, 1981:131-64.
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