Factors Affecting Maternal Mortality and Morbidity Among American Indians
JOHN C. SLOCUMB, iMD, SMH, and STEPHEN J. KUNITZ, MD, PhD
SINCE THE FIRST ROUTINE recording of maternal mortality in the United States in 1915, a steady decline in the rates has been reported. The decline was minimal between 1915 and 1930, but from 1930 to 1950 it dropped precipitously-almost 90 percent. Most of these years preceded the antibiotic era, and the reduction in deaths presumably was related to improved maternal care; increasing use of hospitals for deliveries; increasing safety of hospital deliveries as antisepsis and safer delivery room techniques became widespread; improvements in fluid therapy and blood banking; and development of maternal mor-
tality committees,(1-3). Toward the end of this period, about 1945, the sex ratio (number of males per 100 females), which had been declining gradually since the beginning of the century, finally reversed-females began to outnumber males in the general population for the first time in U.S. history. Although many factors may have influenced this shift, a shift that is commonly observed as populations undergo "modernization" or industrialization, an important contributing factor was the decline in maternal mortality (4). The same shift in sex ratio occurred among American Indians 10 to 15 years later (4).
D1 Dr. Slocumb is associate professor, Department of Obstetrics and Gynecology, University of New Mexico School of Medicine. Dr. Kunitz is associate professor, Department of Preventive Medicine and Community Health, University of Rochester School of Medicine and Dentistry, Rochester, N.Y. Tearsheet requests to John J. Slocumb, MD, University of New Mexico School of Medicine, Department of Obstetrics and Gynecology, 2211 Lomas, Blvd., NE., Albuquerque, N. Mex. 87106.
Despite the many improvements made in health care for American Indians, accessibility continues to be a problem for many tribes, including the Navajos. However, maternal mortality and the male to female ratio have declined, lagging perhaps 8 to 10 years behind the rates for the general population. The following comparison of U.S. and American Indian maternal mortality rates per 100,000 live births shows a 1.4 to 2.7 higher rate among Indians. Number of Indian Year deaths 1935 ........... 77 1940 ........... 69 1945 ........... 57 1950 ........... 35 1958 ........... 16 1963 ........... 24 1966 ........... 16 22 1969-71 ........
Indians
922 723 566
262 83 84 55 34.5
Rate Non-Indians
Relative risk
582 376 207 83 37
1.6 1.9
2.7 2.1 2.2
36
2.3
29 24.2
1.9 1.4
SOURCE: references 13 and 14.
Reports of studies of maternal mortality among American Indians have been published since the 1930s. Sterling (5) reviewed 1,815 hospital deliveries among Chippewas, Sioux, and Navajos in 1930 and 1931; 10 maternal deaths were reported-612 per 100,000 live births-a rate comparable to that of 695 for the general U.S. population in 1929. But if home deliveries had been included, the rate would likely have been a great deal higher. Aberle (6), for instance, in a review of maternal deaths among the Pueblos in New Mexico from 1927 through 1932, noted a death rate due to "the puerperal state" of 292.7 per 100,000 females 10 to 55 years old compared to 38.4 for the same age group in the U.S. population in the census registration area. Aberle remarked that "Hrdlicka in 1908 pointed out the excess of males among the relatively peaceful Rio Grande Pueblos. In a community havJuly-August 1977, Vol. 92, No. 4
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ing a high maternal mortality and no concomitant male mortality, a shift in the sex ratio would be inevitable." On the other hand, White (7) was not convinced that high maternal mortality accounted for the high male to female ratio at Zia Pueblo in the 1930s, although he did observe a decline in the sex ratio between the 1800s and the 1950s. It does seem, however, that the death rates of Navajo males and females changed differentially, and presumably this has had some impact on the present population structure (4). Johnston (8) observed that "It can be concluded that Navajo mortality . .. has declined in the period from 1945 to 1955. This decline is especially noteworthy since 1950, and is stronger in the female segment of the population than the male." McCammon (9) described 475 deliveries between 1948 and 1950 at the Indian Health Service (IHS) hospital on the Navajo Reservation at Fort Defiance, Ariz. Two maternal deaths occurred during that period, one from heart disease and the other from tuberculosis-a rate of 421 deaths per 100,000 live births. Vaughn (10) reported the following rates for maternal deaths in New Mexico between 1956 and 1966: for Apaches, Navajos, and Pueblos combined, 119 per 100,000 live births; for Spanish-Americans, 69.8; and for Anglo-Americans, 23.9. In British Columbia, 145 maternal deaths occurred between 1955 and 1965 (11, 12). Although Indians comprised only 2.4 percent of the population, they accounted for 16.1 percent of the maternal deaths and 5.7 percent of the live births. Their maternal mortality rate was 109 per 100,000 live births compared to 34.6 for non-Indians, a relative risk of 3.15. In this paper, we report several causes of maternal morbidity and mortality among American Indians generally and Navajos in particular and describe changes in the implementation and use of several preventive maternal health practices among the Navajos.
tion group as one is likely to find in the United States. Particularly in the Southwest, Indians are likely to be treated either at IHS facilities or at others that provide care under contract with the IHS. However, there are some losses from the system because of (a) the use of facilities such as some mission hospitals that do not have contracts with the IHS, (b) out-of-pocket or third-party payments for hospitalization, (c) failure to seek care, and (d) outpatient care for certain conditions. Despite these losses, the vast majority of Navajos use the facilities for which data are available, and the data we discuss are limited to these facilities. The Fort Defiance hospital serves between 10,000 and 15,000 Indians, living primarily on the southeastern portion of the Navajo Reservation in northeastern Arizona and northwestern New Mexico. During the 3 years from July 1968 to June 1971, Dr. George Walter and one of us (J.C.S.) kept records on all 1,885 deliveries at that hospital. These records included prenatal care, certain demographic variables such as age, race, and tribal affiliation, pregnancy outcome and management, methods of labor and delivery, and maternal and fetal complications. The data published after responsibility for care passed from the Bureau of Indian Affairs to the Public Health Service were based on information provided by the Bureau of the Census, special surveys by the IHS (14), and State health department records. Our material relating to maternal mortality comes primarily from the health department records and is subject to an unknown amount of error as a result of both underreporting of vital events and uncertainties of diagnosis even when events were reported.
Sources of Data We used three sources for our data: (a) computer
Methods and Findings Causes of maternal mortality. Using the IHS data for 1940-53 (13), we divided the period into two intervals, 1940-45 and 1946-53. First, we applied the maternal mortality rates from the general population to the number of births of Indians in each interval to calculate an expected number of maternal deaths, under the assumption that the rates for In-
tapes of all discharges from IHS and contract facilities in the Navajo and Phoenix Area Offices during fiscal years 1972 and 1973 (July 1, 1971-June 30, 1972, and July 1, 1972-June 30, 1973), (b) clinical data on all deliveries at the IHS hospital at Fort Defiance between July 1, 1968, and June 30, 1971, and (c) material published by the Indian Health Service in 1957 (13). The IHS data for fiscal years 1972 and 1973 represent as nearly complete coverage of any popula-
dians and non-Indians were similar. The observed number of Indian deaths in 1940-45 was 333 and the expected 163. The comparable figures for 1946-53 were 287 and 101. Thus, the Indian deaths were 2.04 times the expected number in the first period and 2.84 times the expected number in the second, reflecting a more rapid decrease in non-Indian maternal mortality in the immediate post-war years. We next compared the number of Indian maternal deaths for the most common causes in the two
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intervals. The figures shown in the following table indicate that the decline in mortality was attributable primarily to a reduction in deaths from sepsis, reflecting among other things mentioned previously the introduction of antibiotics in the post-war years. Causes of Indian maternal mortality Sepsis .... Toxemia ..... Hemorrhage ...... All others ......
Number of deaths 1 ...........
.......... ......... ..........
1940-45 83 85 60 105
1946-53 38 84 76 89
1 X23 = 16.63, P