Racial and Ethnic Disparities in Maternal Mortality in the United States KYRIAKOS S. MARKIDES, PHD UNIVERSITY OF TEXAS MEDICAL BRANCH GALVESTON, TEXAS PRESENTED AT THE HOWARD TAYLOR INTERNATIONAL SYMPOSIUM MATERNAL MORTALITY, WASHINGTON, D.C., ANNUAL CLINICAL MEETING OF THE AMERICAN ASSOCIATION OF OBSTETRICS AND GYNECOLOGY, MAY 3, 2011.
Socioeconomic, racial and ethnic disparities in health remain wide in the United States. The greatest and most persistent are racial and present in: Infant mortality Low birth weight Total mortality Life expectancy at every age, except, perhaps at very advanced ages (85-90 years and older). High mortality from major causes of death: Cardiovascular, Cancer.
WHO (2010) Trends in Maternal Mortality: 1990-2008 358,000 maternal deaths worldwide in 2008; down from 546,000 in 1990 (34% decline). 355,000 (99%) were in developing countries with subsaharan Africa and South Asia accounting for 313,000 deaths, or 87% of the total. Maternal Mortality Ratio (MMR) in developing countries was 290 deaths/100,000 live births, vs. 14 in developed countries.
WHO (2010): continued According to the 1992 ICD-10 of WHO Maternal mortality refers to: The death of a woman while pregnant or within 42 days of termination of pregnancy, from any cause related to or aggravated by the pregnancy or its management; but not from accidental or incidental causes. (pg.4). Because of improvements in technologies and life sustaining procedures, increasingly more women survive adverse outcomes of pregnancy and delivery beyond the 42 days. Such late maternal mortality up to 365 days is now included in the definition employed in countries with advanced civil registration systems.
WHO (2010): continued Estimates for 1990 to 2008 presented are based on new and improved methodology and cannot be compared to previous estimates. The MMR for the U.S. increased from 12/100,000 in 1990, to 24/100,000. Other developed countries showing increases: Canada: 6-12 Finland: 7-8 United Kingdom: 10-12
WHO (2010) continued The U.S. ratio in 2008 was higher than the ratios of most developed countries. Part of the poor U.S. international standing is the result of racial disparities (Tucker et al, 2007). An analysis of 181 countries from 1980 to 2008 using the broader definition (up to 365 days) experienced a substantial increase in maternal mortality among developed countries. (Hogan et al, 2010)
Reasons for increases in U.S. MMR: Approximately 40-50% may be due to administrative changes, including improved ascertainment of maternal mortality on death certificates. The remainder is likely to be real. (Main, 2010) There is evidence in severe maternal morbidity and major complications from 1998 to 2005 (Kuklina et al, 2009; Jamieson et al, 2009; Callaghan, Kuklina et al, 2010; Bateman, Berman, et al; Cang and King, 2008).
Reasons for increases in U.S. MMR (Continued) Main (2010). Possible Factors: Intermittent insurance coverage of some mothers with underlying medical conditions. Increase in older mothers Increases in obese and very obese mothers Increases in requested caesarian births Emerging infection (HIV/AIDS; H1N1 in 2009). Racial disparities remain high
Racial Disparities in Maternal Mortality (continued)
Racial Disparities in MMR (continued) Racial Disparities in maternal mortality persist after controlling for socio-economic status differences. (Lang and King 2005; Main, 2010; Walker and Chestnut, 2010). Such racial disparity parallels a persisting racial difference in infant mortality. African Americans continue to have about twice the infant mortality rate of non- Hispanic whites. While socioeconomic factors account for some of the difference, a racial disparity persists after controlling for socioeconomic status differences. (Collins and David, 2009; Goldenberg and Culhane, 2007; Walker and Chestnut, 2010.) Reasons parallel those for excess maternal mortality.
Racial Disparities in MMR (continued) A 2003 CDC report on pregnancy-related mortality surveillance during the 1990 s noted that the racial disparity in maternal mortality was the highest among the maternal and child health indicators. African American women at any education level had mortality ratios that were three to four times those for white women (much higher than the racial disparity in infant mortality discussed above). CDC, 2003.
Racial Disparities in MMR (continued) In one analysis it was found that African American women did NOT have significantly greater prevalence rates of preeclampsia, eclampsia, abruptio placentae, placenta previa and postpartum hemorrhage, than white women during 1988-1999. However, they had significantly higher mortality from each of these conditions. Thus the racial disparity results from a higher case-fatality rate (Tucker et al, 2007).
Racial Disparities in MMR (continued) Factors: Lack of prenatal care Lack of access to adequate care High rates of co-morbidity, or preexisting conditions. Socioeconomic disadvantages thus lower access to and use of prenatal care.
Racial Disparities in MMR Factors: (continued) Transportation problems Skepticism regarding professional healthcare Greater likelihood to develop certain complications such as peripartum cardiomyopathy, and hypertension even when one controls for these potential confounders, African American women still bear a significant proportion of the maternal mortality burden (Lang and King, 2008, pg. 522)
Racial Disparities in MMR Factors: (continued) Potential factors not fully appreciated include: Differences in nutrition Stress levels Family structures Genetics A greater appreciation of these and other factors is needed to guide prevention and treatment strategies.
Hispanic/Non-Hispanic/White Disparities The Hispanic population of the U.S. numbers more than 50 million and is expected to reach 120 million by 2050 (30 % of total). Growth is due to high immigration rates and increased fertility. Approximately two-thirds of these are of Mexican origin; Central and South American origin; and Puerto Rican and Cuban origin.
Hispanics (except Cuban Americans are Socioeconomically disadvantaged, but have favorable overall mortality Markides and Coreil, 1986 AN EPIDEMIOLOGIC PARADOX Risk Factor Profiles High rates of DIABETES High OBESITY Similar rates of hypertension, Cholesterol High SMOKING rates among men, lower among women (fewer cigarettes). Cuban American males smoke the most High ALCOHOL (binge) drinking rates among women increases with acculturation Low rates of physical ACTIVITY Strong FAMILIES Migration Selection
Recent Evidence of a Salmon Bias Turra & Elo (2008) used the Medicare-NUDIMENT data to examine the existence of a salmon bias. Data supported a salmon bias: foreign-born social security beneficiaries living abroad had higher mortality rates than foreign-born beneficiaries living in the U.S. Too small to explain mortality advantage. Effect of salmon bias on death rates is partially offset by the high mortality of Hispanic emigrants returning to the U.S.
A Different Test of the Salmon Bias Hummer and colleagues (2007), examined infant mortality rates among Hispanics by nativity and in comparison to non-hispanic whites. They found that first hour, first day and first week mortality rates among infants born in the U.S. to Mexican immigrant women are about 10 % lower than those of infants of U.S. born non-hispanic white women. It is unlikely that such favorable rates are the result of out-migration of Mexican origin women and infants.
UNITED STATES TABLES BY HISPANIC ORIGIN (2006) E. Arias, NCHS, 2010
Hispanic Paradox in Infant Mortality Despite their generally disadvantaged socioeconomic situation, most Hispanic origin populations have rather favorable infant mortality rates (Brown et al, 2007; Gonzalo-Quintero et al; Hummer et al, 2007. Literature reviews of the Hispanic Paradox have suggested that it is especially present in infant mortality and old-age mortality (Franzini et al, 2001, Hummer et al, 2007; Markides and Eschbach, 2011).
Hispanic Paradox in Infant Mortality Low levels of education, income, and health insurance coverage among Hispanics compared with non-hispanic Whites is thought to put them at considerably greater risk of negative health outcomes, including infant mortality. However, they have rather favorable health outcomes. Such favorable health outcomes are primarily attributed to immigrants, most of whom are of Mexican origin.
Hispanic Paradox in Maternal Mortality CDC rates from 1997-2003 for all Hispanics show somewhat lower Maternal Mortality rates than for non- Hispanic Whites, and considerably lower than those for African Americans with whom they share socioeconomic conditions. No data by type of Hispanic origin were Earlier CDC data for 1979-1992 on pregnancy-related mortality were consistent with the above. Cuban women were the most advantaged and Puerto Rican, the least; Mexican-origin women were in between. (Hopkins et al, 1999).
Hispanic Paradox in Maternal Mortality (continued) Because minority status and socioeconomic resources contribute to poor health outcomes, we expected Hispanic women to fare worse than non-hispanic White women, but we found the disparity in the risk of pregnancy-related death between black and Hispanic women striking. (Hopkins et al, 1999) Because Hispanic women are similar socioeconomically to black women, further study is needed of the factors that contribute to this Hispanic Paradox in pregnancy related mortality. (Hopkins et al, 1999)
Hispanic Paradox in Maternal Mortality (continued) Guendelman and Colleagues (2006) found that despite their lower education and relative poverty, Mexican-born women experienced lower odds of any maternal morbidity than U.S. born Mexican American women, which is consistent with the Hispanic Paradox of favorable birth outcomes. However the foreign-born did not show an advantage in maternal mortality. Migration selection, health behaviors, and cultural factors are important.
Conclusion Racial and Ethnic health disparities in maternal mortality parallel those in infant mortality, overall mortality, and life expectancy. In fact, the black/white disparity in maternal mortality appears to be greater than the disparity in other health indicators and suggests that there is considerable room for improvement through prevention and treatment strategies.
Conclusion (continued) There is evidence of a Hispanic Paradox in maternal mortality which parallels the Hispanic Paradox in infant mortality. However, there does not appear to be an overall Hispanic or Mexican-origin advantage as there is infant and overall mortality. Migration selection, cultural factors and health behaviors. Evidence of negative acculturation in all health indicators which may lead to more negative outcomes in the future.
Conclusion Migration selection, cultural factors and health behaviors. Evidence of negative acculturation in all health indicators which may lead to more negative outcomes in the future The literature on Hispanic maternal Mortality and Maternal health overall is rather scarce despite its large size and high fertility.