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A thirty-year review of maternal mortality in Oklahoma, 1950 through 1979
A thirty-year review of maternal mortality in Oklahoma, 1950 through 1979 Vijayakumar Moses, M.B., B.S., M.D., Sara Reed DePersio, M.D., M.P.H., Dick Lorenz, M.S.P.H., Mark W. Oberle, M.D., M.P.H., Roger Rochat, M.D., and Autora Fermo, M.D. Oklahoma City, Oklahoma, and Atlanta, Georgia Oklahoma's Maternal Mortality Committee has been active since 1941. During the 30-yt;Jar period 1950 through 1979, the committee reviewed in detail 75.9% of the pregnancy-related deaths that occurred in Oklahoma. The maternal mortality ratio in 1950 was 95.1/100,000 live births, and for 1979 it was 8.1/100,000 live births, a decrease of 91 .5%. The risk of death from childbearing remained greater for black women than for American Indian or white women throughout the three decades. For American Indian women, the risk of death associated with pregnancy has decreased and is almost equal to the risk for white women. The Maternal Mortality Committee estimated that two thirds of Oklahoma's maternal deaths were preventable. The proportion of deaths judged preventable did not vary substantially during the study period. We conclude that maternal mortality in Oklahoma can be reduced to fewer than three deaths per 100,000 live births. Intensive monitoring and investigation of deaths and their causes by local maternal mortality committees continues to be an important mechanism for obtaining infoPmation to assist health workers in the prevention of deaths. (AM J OssTET GYNECOL 1987;157:1189-94.)
Key words: Maternal mortality, Oklahoma, race-specific rates, Native American maternal mortality
The prevention of maternal deaths remains one of the foremost goals of obstetrics, and the maternal mortality ratio has been a widely used measure of the quality of maternal health care. We report here a descriptive epidemiologic study performed on the reported pregnancy-related deaths occurring over 30 years in the State of Oklahoma from 1950 through 1979. This included the analysis of maternal mortality ratios by age, causes of death, and trends over time in three racial groupings-white, black, and American Indian. Preventability factors were also studied.
Material and methods The Oklahoma Maternal Mortality Committee was organized in 1941' by the Oklahoma State Medical Association, in cooperation with the Maternal and Child Health Service (MCHS) of the Oklahoma State Department of Health. Pregnancy-associated deaths were From the Maternal and Child Health Services, Oklahoma State Department of Health, Oklahoma City, and the Division of Reproductive Health, Centers for Disease Control, Atlanta. Supported by the Rockefeller Foundation and the Centers for Disease Control's International Training Program in Family Planning Evaluation and Epidemiology. Presented at the First International Symposium on Public Health in Asia and the Pacific Basin, Honolulu, Hawaii, March 7, 1983. Received for publication May 4, 1987; revised july 24, 1987; accepted july 24, 1987. Reprint requests: Program Evaluation Branch, Division of Reproductive Health, Center for Health Promotion and Education, Centers for Disease Control, Atlanta, GA 30333 (Dr. Oberle).
identified by Oklahoma vital statistics from death certificates and sent to MCHS. In order to learn more about the deaths, the committee requested additional information from the physician who had signed the death certificate and from the physician who had treated the mother. All identifying information was removed from the collected information and sent to the committee. After review by the committee, the deaths were classified according to the Guide for Maternal Death Studies published by the American Medical Association (AMA) in 1964. 2 Causes of death have been reclassified by the codes given in the International Classification of Diseases, ninth revision, Clinical Modifications (ICD-9-CM), volume 1, 1979. 3 This edition was selected because it has a larger number of pregnancy-related causes of death than previous revisions of the lCD (namely revisions 6, 7, and 8, which were in use during the study period), and the ninth edition is the one in currentuse. The ICD9-CM differs from the ICDA-8 and the AMA's classification 2 of maternal deaths in the following respects: 1. ICD-9-CM includes other concurrent conditions in the mothers, such as diabetes and cardiovascular diseases that complicate pregnancy, childbirth, and the puerperium. The AMA defined deaths due to these conditions as indirect obstetric deaths, while ICDA-8 classified them as deaths due to non-pregnancy-related causes. 1189
1190
Moses et al.
November 1987 Am J Obstet Gynecol
en
deaths could be attributed to the attending physician, to the patient, or to both .
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1950- '55- '60- '65- '70- '751954 '59 '64 '69 '74 '79
Fig. 1. Maternal mortality ratio by race and by 5-year intervals, Oklahoma, 1950 through 1979.
2. ICD-9-CM includes deaths from maternal infection and parasitic conditions such as venereal diseases and tuberculosis. These conditions are included in the AMA's definition of nonrelated deaths. These conditions are not included in the pregnancy-related causes of deaths in ICDA-8. 3. ICD-9-CM limits maternal deaths to those occurring within 42 days of termination of pregnancy, while ICDA-8 has a time period of up to 1 year after pregnancy termination and the AMA uses a time period of 90 days after pregnancy termination. In ICD-9-CM, deaths that were classified under codes 630-676 were called maternal deaths. The maternal mortality ratio has been calculated with maternal deaths as the numerator and live births used as the denominator! Thus the maternal mortality ratio is the number of maternal deaths per 100,000 live births. Because Oklahoma's racial groups differ in the distribution of maternal ages, a crude maternal mortality ratio and an age-adjusted maternal mortality ratio was calculated for each racial group, with the aggregate maternal age distribution during 1950 through 1979 as the standard population. 5 The Maternal Mortality Committee, using the Guide for Maternal Death Studies published by the AMA! determined whether these maternal deaths could have been prevented. The Maternal Mortality Committee also attempted to establish whether the primary responsibility for these maternal
Results
A total of 632 maternal deaths among Oklahoma residents were reported to the Maternal Mortality Committee during the 30-year period from 1950 through 1979. In addition, the committee received reports of 61 pregnant women who died of causes unrelated to pregnancy, such as malignancies and automobile accidents. These latter deaths were excluded from the analysis. There were 1,405,382live births in Oklahoma during the 30-year period. Thus the maternal mortality ratio in Oklahoma for 1950 through 1979 was 45.1 per 100,000 live births. The maternal mortality ratio in 1950 was 95.1 per 100,000 live births, and in 1979 it was 8.1 per 100,000 live births. The maternal mortality ratio decreased in the 1950s by 40.4% and in the 1970s by 49.2% (Fig. 1). The age-specific maternal mortality ratio decreased for each age group during the three decades (Table I). During the 1950s, the age-specific maternal mortality rates were slightly higher for women 15 to 19 years old than those 20 to 24 years old and were highest for older women. The mortality ratio among teenagers declined more dramatically than the ratio for women aged 20 to 24, so that after the 1950s the maternal mortality ratio increased directly with increasing age. Of the 632 deaths, 64.2% occurred among white women, 27.1% among black women, and 7.2% among American Indian women. Black women had the highest maternal mortality ratio throughout the study period (Fig. 1). The age-adjusted maternal mortality ratio decreased among white and American Indian women during the three decades. Black women showed a more rapid reduction in the mortality ratio between the first two decades, but the age-adjusted maternal mortality ratio for black women actually increased in the 1970s (Table II). To compare maternal mortality ratios in the three racial groups, we divided two race-specific maternal mortality ratios to obtain a ratio of ratios or a "risk ratio." Thus for pregnant black women the risk of pregnancy-related death was 4.6 times greater than the risk for white women during the first decade of the study; this ratio decreased in the 1960s (2. 7) but increased in the last decade (4.8). On the other hand, American Indian women's risk of pregnancy-related death was 3.2 times greater than the risk for white women during the 1950s, but this risk ratio steadily declined to 1.2 in the 1970s (Table II). The proportion of maternal deaths attributed to hemorrhage, preeclampsia-eclampsia, and abortion complications (which were the three leading causes of maternal mortality) declined from 1950 through 1979,
Maternal mortality in Oklahoma, 1950-1979
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Table I. Number of maternal deaths and maternal mortality ratio per 100,000 live births by age and decade, Oklahoma, 1950 through 1979 Age group
Total (1950-1979)
(yr)
Ratio
15-19 20-24 25-29 30-34 35-39 2=40 Total
I
1950-1959
I
1960-1969
No. of deaths
Ratio
26.6 25.6 46.2 71.2 13,3.5 253.4
75 135 156 114 96 55
46.7 34.2 70.8 105.9 166.1 334.2
41 61 87 74 58 36
19.0 22.7 39.6 56.7 114.0 206.9
45.1
631
65.2
357
37.7
No. of deaths
Ratio
I
1970-1979
I
No. of deaths
Ratio
19* 40 40 28 28 16
15.3 19.7 25.5 29.5 80.6 95.5
15 34 29 12 10 3
25.6
103
171
No. of deaths
*Includes one 14-year-old girl in 1967.
Table II. Age-adjusted maternal mortality ratio per 100,000 live births by race, decade, and risk ratio, Oklahoma, 1950 to 1979 Total (1950-1979) Ratio
Race All races White Black Indian Risk ratio Black/white Indian/white
45.1 34.1 129.5 67.4 3.8 2.0
I
1960-1969
1950-1959
No. of deaths
Ratio
632 406 171 55
65.2 46.4 214.3 144.3
I
No. of deaths
Ratio
357 220 102 15
37.7 31.0 83.2 53.7
4.6 3.2
while the proportion of deaths due to puerperal infections and ectopic pregnancy increased (Table III). Of the 632 maternal deaths, the marital status of 590 women was known (93.3%). Among deaths of women with known marital status, a total of 86.4% of maternal deaths occurred among married women. In the 1950s 89% of maternal deaths occurred among married women, while in the 1970s this percentage declined to 80.4%. Data on births by marital status were not available to calculate a maternal mortality ratio by mother's marital status. Throughout the period, autopsies were performed in 203 maternal deaths in Oklahoma. The proportion of deaths with autopsies reported increased from 11.3% in 1950 to 1954 to 57.1% in 1975 to 1979. Similar increases occurred among all racial groups. Although the total number of deaths among women of reproductive age decreased by 14% between 1950 to 1954 and 1975 to 1979, the proportion of maternal deaths decreased even more. Thus in 1950 to 1954 maternal deaths represented 6.5% of all deaths among women aged 15 to 44 while in 1975 to 1979 maternal deaths represented only 1.2%, a relative decrease of 81.5% (data not shown). This decrease occurred throughout the period among white and American In-
2.7 1.7
I
1970-1979
No. of deaths
Ratio
172 138 40 54
25.6 19.3 92.6 22.7
) No. of deaths
103 68 29 6
4.8 1.2
dian women; however, among black women, a slight increase occurred in the last 5 years of the study. The Oklahoma Maternal Mortality Committee assessed preventability and responsibility factors in 75.0% of the maternal deaths. Throughout the study period, preventable factors were identified for 66.9% of those evaluated. The number of maternal deaths that had preventable factors identified decreased from 105 in 1950 to 1954 to 25 in 197 4 to 1979, a relative decrease of 76.2% (Table IV), while the total number of maternal deaths decreased from 224 in 1950 to 1954 to 36 in 1974 to 1979, a relative decrease of 83.9%. The committee attempted to establish whether the primary responsibility for these maternal deaths was attributable to physician, patient, or both. They found that physicians were responsible for factors that could have been prevented in 52.1% of the assessed maternal deaths. Patients were responsible for factors that could have been prevented in 33.8% of the assessed deaths, and the physicians and patients combined were responsible for preventable factors in 11.7% of the maternal deaths. The percentage of maternal deaths with preventable factors that were the responsibility of the physician increased from 41.9% in 1950 to 72.2% in 1965, then declined to 40% in 1975 to 1979. In the same period,
1192 Moses et al.
November 1987 Am J Obstet Gynecol
Table III. Causes of maternal deaths by decade and race, Oklahoma, 1950 through 1979 (percentage distribution) All races
Cause
Total (1950-1979)
1950-1959
Hemorrhage Preeclampsia-eclampsia Complications of abortion Puerperal infection Ectopic pregnancy Amniotic fluid embolism Pulmonary embolism Complications of anesthesia Cardiovascular disorder Others Total No. of deaths
24.4 17.1 8.7 7.2 7.0 4.3 4.3 5.2 7.0 14.8 100.0 632
27.2 20.5 8.7 3.5 6.2 1.7 4.2 4.8 8.7 14.5 100.0 357
1
1960-1969
Race-specific (1950-1979) 1
1970-1979
White
18.5 12.6 7.8 15.5 11.7 5.8 1.9 4.9 3.9 17.4 100.0 103
24.9 15.3 8.1 7.4 5.2 5.2 5.7 4.4 7.6 16.2 100.0 406
22.1 12.8 9.3 9.9 5.8 8.7 5.8 6.4 5.2 14.0 100.0 172
I
Black
21.0 19.9 9.4 4.1 12.9 2.3 1.8 8.2 6.4 14.0 100.0 171
I
Indian
30.9 21.8 10.9 16.4 1.8 3.6 1.8 1.8 3.6 7.4 100.0 55
Table IV. Responsibility for preventable factors resulting in maternal deaths assessed by Maternal Mortality Committee, Oklahoma, 1950 through 1979 (percentage distribution) Years Responsibility
1950-1954
1955-1959
1960-1964
1965-1969
1970-1974
1975-1979
Physician Patient Physician and patient Other Total
41.9 40.0 15.2 2.9 100.0
50.4 34.0 2.4 3.2 100.0
59.6 25.4 12.8 2.2 100.0
72.2 16.7 11.1 0.0 100.0
61.5 28.2 5.2 5.1 100.0
40.0 56.0 4.0 0.0 100.0
Estimated No. of preventable deaths
105
65
47
36
39
25
the percentage of maternal deaths with preventable factors that were the responsibility of the patient decreased gradually from 40.0% in 1954 to 16.7% in 1965 to 1966, then climbed up to 56.0% in 1975 to 1979. Comment
The decline of maternal mortality in Oklahoma closely parallels that of the United States as a whole. Oklahoma's maternal mortality ratio, as calculated by the National Center for Health Statistics, was 85.21100,000 live births in 1950 and 10.11100,000 live births in 1979, a decrease of 88.2%. During the same period, U.S. maternal mortality ratios decreased by 90.6%. Studies in several states found that the incidence of maternal mortality was higher than that reported through the standard vital records reporting systems. 6 ' 9 The method of ascertaining maternal deaths through maternal mortality committee review may be more complete than using national vital statistics alone. 8 The rates observed in this study are higher than those obtained from the National Center for Health Statistics. These studies have underscored the importance of im-
proved surveillance in identifying maternal deaths. The maternal mortality committee is one way of clarifying the cause of maternal deaths. Many reported studies calculated the maternal mortality ratio with direct obstetric death as defined by the guidelines set by the AMA used as the numerator. 9 · 10 Rochat 12 emphasized that if pregnancy-related deaths were to be used as the numerator instead of direct obstetric deaths, the ratio may be twice as high as the current reported maternal mortality ratio. ICD-9-CM comes closer to measuring pregnancy-related deaths than the AMA classification or previous revisions of the lCD. For the 30-year period of this study, use of the ICD-9-CM classification resulted in 23.8% more deaths classified as maternal deaths when compared with those classified by the AMA's direct obstetric death classification. Smith et al. 13 classified all maternal deaths in the United States from 1974 to 1978 by using ICD-9-CM and ICDA-8 and found that the use of ICD-9-CM resulted in an increase of 8.8% over ICDA-8 in the number of deaths classified as maternal deaths. All maternal deaths identified in this study occurred less than 42
Volume 157 Number 5
days after delivery and met the ICD-9-CM definition of maternal death. The race-specific analysis revealed that among black and American Indian women, maternal mortality ratios are still higher than the ratio for white women. The risk of death from childbearing remained greater for black women, while for American Indian women, the risk of death due to pregnancy has decreased and is similar to that o£ white women. The improvement in the American Indian maternal mortality ratio in Oklahoma may reflect improvements in obstetric care, improvements in socio-economic status, or an artifactual difference in reporting racial status on birth or death certificates. The important observation from the perspective of health care services is that the difference between ratios for black women and those for white women did not decrease. In fact, this difference has increased in the last decade. This difference is due in part to the increased proportion of maternal deaths of black women that are due to ectopic pregnancy and preeclampsia-edam psia. The percentage of deaths due to maternal causes among black women of reproductive age was higher than the percentage of deaths due to maternal causes among American Indian and white women. Factors contributing to this elevated risk are that black teenagers have a higher fertility rate than white teenagers in Oklahoma 14 and that black women may wait until later in their pregnancies than American Indian or white women to seek prenatal and obstetric care. The study of Buehler et al. 15 revealed that black women aged 35 or older are at significantly higher risk of death than white women and their risk was even greater for deaths associated with abortive outcomes (including ectopic pregnancy). A significant finding was the higher rate of deaths in ectopic pregnancy among older black women. This reflects the fourfold higher rate of ectopic pregnancies among black women aged 35 and older compared with white women in the United States. One contributing factor to death from ectopic pregnancy is a failure to diagnose early pregnancy among women aged 35 and older. The diagnosis of ectopic pregnancy by physical examination is more difficult in these women because a greater proportion are overweight. 16 Progress has been made in reducing the number of maternal deaths in Oklahoma, especially those due to hemorrhage, preeclampsia-eclampsia, and complications of abortion. In 1965, Crosbt 7 reported that hemorrhage was the leading cause of maternal deaths, and a later study by Jimerson and Crosbt 8 showed that hemorrhage continued to be the leading cause of maternal death in Oklahoma. More recently, hemorrhage has dropped behind preeclampsia-eclampsia as the leading cause of maternal deaths.'" The number of maternal deaths due to preeclampsia-
Maternal mortality in Oklahoma, 1950-1979
1193
eclampsia fell precipitately between the 1950s and the 1960s. Tyler and Saeger2" reported that preeclampsiaeclampsia was the leading cause of pregnancy-related deaths among American Indian women in eastern Oklahoma in 1965. Vaughn 21 reported that 30% of total maternal deaths among American Indians in New Mexico were due to preeclampsia-eclampsia. Our study also showed a similar pattern among American Indians in Oklahoma. Pregnant American Indian women are two and a half times more likely to die of preeclampsiaeclampsia than are white women. Early identification of high-risk women may well prevent maternal mortality caused by preeclampsia-eclampsia. 2" Although complications of abortion were the third leading cause of maternal deaths in Oklahoma over the entire period, there were no deaths due to complications of induced abortion during the last 5 years. This may be due to widespread use of effective methods of contraception and to the availability of safe, legal abortion in Oklahoma. Among all maternal deaths, the percentage of women who were single has more than doubled in the 30-year period; this phenomenon is particularly notable among black women. These deaths may reflect the trend of more births occurring out of wedlock in recent years and the higher percentage of out-of-wedlock births among black teenage women than among American Indian or white women.'' Since preventable factors were identified in two thirds of the maternal deaths evaluated, maternal mortality in Oklahoma could be reduced to three deaths per 100,000 live births. However, achieving this residual reduction in mortality will require intensive efforts to understand the events leading to maternal death. Clinical data are particularly useful in determining the evaluation of events that led to the woman's death, but clinical data alone do not always provide adequate information to accurately classify the cause of death. Autopsies provide useful additional information. Although the proportion of maternal deaths evaluated with autopsies increased over the three decades studied, clinicians should continue to strive to obtain permission for autopsies to determine the specific pathologic causes of maternal death. Although the recent dramatic decrease in Oklahoma's maternal mortality is encouraging, continued effort in mortality surveillance and health education will be necessary to meet these objectives. REFERENCES L Marmo! JG, Scriggins AL, Vollman RF. History of the maternal mortality study committees in the United States. Obstet Gynecol 1969;34:123. 2. Committee on Maternal and Child Care of the Council on Medical Services. A guide for maternal death studies; American Medical Association. 3. World Health Organization. International classification of
Moses et al.
4. 5. 6.
7. 8.
9. 10.
11. 12. 13.
diseases. 9th rev. Clinical modification ICD:9. Washington DC: United States Department of Health and Human Services, 1979 vol 1:527. Daniel WW. Biostatistics: a foundation for analysis in health sciences. New York: John Wiley, 1974:368. Mausner JS, Bahn AK. Epidemiology: an introductory text. Philadelphia: WB Saunders, 1974:136. Rochat RW. The magnitude of maternal mortality: definitions and methods of measurement. In Candy U, Rafnam SS. Prevention and treatment of contraceptive failure. New York: Plenum Press, 1986:201-14. Ziskin LJ, Gregory M, Kreitzer M. Improved surveillance of maternal deaths. IntJ Gynaecol Obstet 1979;16:281. Speckhard ME, Comas- Urrutia AC, Rigan-PerezJG, Adamsons K. Intensive surveillance of pregnancy-related deaths, Puerto Rico, 1978-1979. Bol Asoc Med PR 1985;77:508. Rubin GL, McCarthy B, Shelton], Rochat R, Terry J. The risk of childbearing re-evaluated. Am J Public Health 1981;71:712. Schaffner W, Federspiel CF, Fulton ML, Gilbert DG, Stevenson LB. Maternal mortality in Michigan: an epidemiologic analysis, 1950-1971. Am J Public Health 1977; 67:821. Centers for Disease Control. Maternal mortality: pilot surveillance in seven states. MMWR 1985;34:709. Rochat R. Maternal mortality in the United States of America. World Health Stat 1981 ;34:2. Smith .JC, Hughes JM, Pekow PS, Rochat RW. An As-
November 1987 Am J Obstet Gynecol
14. 15. 16.
17. 18. 19. 20. 21. 22.
sessment of the incidence of maternal mortality in the US. Am J Public Health 1984;74:780. Fermo VA, DePersio SR, Lorenz D, Oberle M. Recent trends in pregnancy among teenagers in Oklahoma. J Okla State Med Assoc 1985;78:169. Buehler JW, Kaunitz AM, Hogue CJ, Hughes JM. Maternal mortality in women aged 35 years or older: United States. JAMA 1986;255:53. Forman MR, Trowbridge FL, Gentry EM, Marks JS, Hogelin GC. Overweight adults in the United States: the behavorial risk factor surveys. Am J Clin Nutr 1986; 49:410. Crosby WM. Hemorrhage as a cause of maternal mortality in Oklahoma. J Okla State Med Assoc 1965;58:490. Jimerson SD, Crosby WM. Maternal mortality in Oklahoma: hemorrhage remains a problem. Okla State Med Assoc 1978;71:197. Jennings R, Crosby W, DePersio S. Preeclampsiaeclampsia: the number one cause of maternal death in Oklahoma.] Okla State Med Assoc 1984;77:107. Tyler C, Saeger A. Maternal health and socioeconomic status of nonreservation Indians. Public Health Rep 1968;83:465. Vaughn B. Maternal deaths in New Mexico, 1956-1966. Rocky Mt Med J 1969;66:65. Kaunitz A, Hughes J, Grimes D, et al. Causes of maternal mortality in the United States. Obstet Gynecol 1985;65: 605.
Anorexia nervosa, bulimia, and pregnancy Donna E. Stewart, M.D., Joel Raskin, M.D., Paul E. Garfinkel, M.D., Ophelia L. MacDonald, M.D., and G. Edick Robinson, M.D. Toronto, Ontario, Canada Of 74 women previously treated for anorexia nervosa or bulimia, 15 had conceived 23 pregnancies when assessed at follow-up. The status of the eating disorder, course of pregnancy and delivery, infant health, and postpartum adjustment are described. Women in whom eating disorders were in remission at conception had greater maternal weight gain and babies with higher birth weights and 5-minute Apgar scores than women who conceived while they still had symptoms of restricting anorexia nervosa or bulimia. Women who had symptoms of eating disorders at conception also had continuance or worsening of these symptoms during pregnancy and the postpartum year. We recommend delay of pregnancy until the eating disorder is truly in remission. (AM J OssTET GvNECOL 1987;157:1194-8.)
Key words: Anorexia nervosa, bulimia, pregnancy, infants
From the Departments of Psychiatry and Obstetrics and Gynecology, University of Toronto, St. Michael's Hospital, and Toronto General Hospital. This work was supported in part by Grant No. 921 from the Ontario Mental Health Foundation to Dr. P. E. Garfinkel from 1985 to 1987. Presented in part to the Canadian Psychiatric Association Annual Meeting, Vancouver, British Columbia, Canada, September 1986, and to the American Society for Psychosomatic Obstetrics and Gynecology Annual Meeting, Point Clear, Alabama, March 25-29, 1987. Received for publication November 4, 1986; revised May 12, 1987; accepted july 14, 1987. Reprint requests: Dr. D. E. Stewart, St. Michael's Hospital, 30 Bond St., Floor 4M, Toronto, Ontario, Canada M5B 1W8.
1194
The high prevalence of anorexia nervosa and bulimia among young women,' combined with more effective treatment of these conditions, has resulted in more of these women eventually becoming pregnant. Little is known about the course of pregnancy in these women and even less is known about the health of their infants. Many psychological conflicts thought to be important in patients with eating disorders concerning adult sexuality, body image, autonomy, dependency, and relationships to parents are highlighted during normal pregnancy. This has led to speculation that pregnancy
Key words: Maternal mortality, Oklahoma, race-specific rates, Native American maternal mortality
The prevention of maternal deaths remains one of the foremost goals of obstetrics, and the maternal mortality ratio has been a widely used measure of the quality of maternal health care. We report here a descriptive epidemiologic study performed on the reported pregnancy-related deaths occurring over 30 years in the State of Oklahoma from 1950 through 1979. This included the analysis of maternal mortality ratios by age, causes of death, and trends over time in three racial groupings-white, black, and American Indian. Preventability factors were also studied.
Material and methods The Oklahoma Maternal Mortality Committee was organized in 1941' by the Oklahoma State Medical Association, in cooperation with the Maternal and Child Health Service (MCHS) of the Oklahoma State Department of Health. Pregnancy-associated deaths were From the Maternal and Child Health Services, Oklahoma State Department of Health, Oklahoma City, and the Division of Reproductive Health, Centers for Disease Control, Atlanta. Supported by the Rockefeller Foundation and the Centers for Disease Control's International Training Program in Family Planning Evaluation and Epidemiology. Presented at the First International Symposium on Public Health in Asia and the Pacific Basin, Honolulu, Hawaii, March 7, 1983. Received for publication May 4, 1987; revised july 24, 1987; accepted july 24, 1987. Reprint requests: Program Evaluation Branch, Division of Reproductive Health, Center for Health Promotion and Education, Centers for Disease Control, Atlanta, GA 30333 (Dr. Oberle).
identified by Oklahoma vital statistics from death certificates and sent to MCHS. In order to learn more about the deaths, the committee requested additional information from the physician who had signed the death certificate and from the physician who had treated the mother. All identifying information was removed from the collected information and sent to the committee. After review by the committee, the deaths were classified according to the Guide for Maternal Death Studies published by the American Medical Association (AMA) in 1964. 2 Causes of death have been reclassified by the codes given in the International Classification of Diseases, ninth revision, Clinical Modifications (ICD-9-CM), volume 1, 1979. 3 This edition was selected because it has a larger number of pregnancy-related causes of death than previous revisions of the lCD (namely revisions 6, 7, and 8, which were in use during the study period), and the ninth edition is the one in currentuse. The ICD9-CM differs from the ICDA-8 and the AMA's classification 2 of maternal deaths in the following respects: 1. ICD-9-CM includes other concurrent conditions in the mothers, such as diabetes and cardiovascular diseases that complicate pregnancy, childbirth, and the puerperium. The AMA defined deaths due to these conditions as indirect obstetric deaths, while ICDA-8 classified them as deaths due to non-pregnancy-related causes. 1189
1190
Moses et al.
November 1987 Am J Obstet Gynecol
en
deaths could be attributed to the attending physician, to the patient, or to both .
:E .... 300
i:O Q)
All Races White Black American Indian
I
>
I
:.J 250
\
I
0 0 0
I
\
200 ci 0
I
I
,... ....Q)
0.
0
I \
\
I
150 '. '.
t1l
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I, I
100
50
.,
·.........
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----
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...........................
----------------___:::: :_<:~.
o~--T---~--~--~--~--~---
1950- '55- '60- '65- '70- '751954 '59 '64 '69 '74 '79
Fig. 1. Maternal mortality ratio by race and by 5-year intervals, Oklahoma, 1950 through 1979.
2. ICD-9-CM includes deaths from maternal infection and parasitic conditions such as venereal diseases and tuberculosis. These conditions are included in the AMA's definition of nonrelated deaths. These conditions are not included in the pregnancy-related causes of deaths in ICDA-8. 3. ICD-9-CM limits maternal deaths to those occurring within 42 days of termination of pregnancy, while ICDA-8 has a time period of up to 1 year after pregnancy termination and the AMA uses a time period of 90 days after pregnancy termination. In ICD-9-CM, deaths that were classified under codes 630-676 were called maternal deaths. The maternal mortality ratio has been calculated with maternal deaths as the numerator and live births used as the denominator! Thus the maternal mortality ratio is the number of maternal deaths per 100,000 live births. Because Oklahoma's racial groups differ in the distribution of maternal ages, a crude maternal mortality ratio and an age-adjusted maternal mortality ratio was calculated for each racial group, with the aggregate maternal age distribution during 1950 through 1979 as the standard population. 5 The Maternal Mortality Committee, using the Guide for Maternal Death Studies published by the AMA! determined whether these maternal deaths could have been prevented. The Maternal Mortality Committee also attempted to establish whether the primary responsibility for these maternal
Results
A total of 632 maternal deaths among Oklahoma residents were reported to the Maternal Mortality Committee during the 30-year period from 1950 through 1979. In addition, the committee received reports of 61 pregnant women who died of causes unrelated to pregnancy, such as malignancies and automobile accidents. These latter deaths were excluded from the analysis. There were 1,405,382live births in Oklahoma during the 30-year period. Thus the maternal mortality ratio in Oklahoma for 1950 through 1979 was 45.1 per 100,000 live births. The maternal mortality ratio in 1950 was 95.1 per 100,000 live births, and in 1979 it was 8.1 per 100,000 live births. The maternal mortality ratio decreased in the 1950s by 40.4% and in the 1970s by 49.2% (Fig. 1). The age-specific maternal mortality ratio decreased for each age group during the three decades (Table I). During the 1950s, the age-specific maternal mortality rates were slightly higher for women 15 to 19 years old than those 20 to 24 years old and were highest for older women. The mortality ratio among teenagers declined more dramatically than the ratio for women aged 20 to 24, so that after the 1950s the maternal mortality ratio increased directly with increasing age. Of the 632 deaths, 64.2% occurred among white women, 27.1% among black women, and 7.2% among American Indian women. Black women had the highest maternal mortality ratio throughout the study period (Fig. 1). The age-adjusted maternal mortality ratio decreased among white and American Indian women during the three decades. Black women showed a more rapid reduction in the mortality ratio between the first two decades, but the age-adjusted maternal mortality ratio for black women actually increased in the 1970s (Table II). To compare maternal mortality ratios in the three racial groups, we divided two race-specific maternal mortality ratios to obtain a ratio of ratios or a "risk ratio." Thus for pregnant black women the risk of pregnancy-related death was 4.6 times greater than the risk for white women during the first decade of the study; this ratio decreased in the 1960s (2. 7) but increased in the last decade (4.8). On the other hand, American Indian women's risk of pregnancy-related death was 3.2 times greater than the risk for white women during the 1950s, but this risk ratio steadily declined to 1.2 in the 1970s (Table II). The proportion of maternal deaths attributed to hemorrhage, preeclampsia-eclampsia, and abortion complications (which were the three leading causes of maternal mortality) declined from 1950 through 1979,
Maternal mortality in Oklahoma, 1950-1979
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Table I. Number of maternal deaths and maternal mortality ratio per 100,000 live births by age and decade, Oklahoma, 1950 through 1979 Age group
Total (1950-1979)
(yr)
Ratio
15-19 20-24 25-29 30-34 35-39 2=40 Total
I
1950-1959
I
1960-1969
No. of deaths
Ratio
26.6 25.6 46.2 71.2 13,3.5 253.4
75 135 156 114 96 55
46.7 34.2 70.8 105.9 166.1 334.2
41 61 87 74 58 36
19.0 22.7 39.6 56.7 114.0 206.9
45.1
631
65.2
357
37.7
No. of deaths
Ratio
I
1970-1979
I
No. of deaths
Ratio
19* 40 40 28 28 16
15.3 19.7 25.5 29.5 80.6 95.5
15 34 29 12 10 3
25.6
103
171
No. of deaths
*Includes one 14-year-old girl in 1967.
Table II. Age-adjusted maternal mortality ratio per 100,000 live births by race, decade, and risk ratio, Oklahoma, 1950 to 1979 Total (1950-1979) Ratio
Race All races White Black Indian Risk ratio Black/white Indian/white
45.1 34.1 129.5 67.4 3.8 2.0
I
1960-1969
1950-1959
No. of deaths
Ratio
632 406 171 55
65.2 46.4 214.3 144.3
I
No. of deaths
Ratio
357 220 102 15
37.7 31.0 83.2 53.7
4.6 3.2
while the proportion of deaths due to puerperal infections and ectopic pregnancy increased (Table III). Of the 632 maternal deaths, the marital status of 590 women was known (93.3%). Among deaths of women with known marital status, a total of 86.4% of maternal deaths occurred among married women. In the 1950s 89% of maternal deaths occurred among married women, while in the 1970s this percentage declined to 80.4%. Data on births by marital status were not available to calculate a maternal mortality ratio by mother's marital status. Throughout the period, autopsies were performed in 203 maternal deaths in Oklahoma. The proportion of deaths with autopsies reported increased from 11.3% in 1950 to 1954 to 57.1% in 1975 to 1979. Similar increases occurred among all racial groups. Although the total number of deaths among women of reproductive age decreased by 14% between 1950 to 1954 and 1975 to 1979, the proportion of maternal deaths decreased even more. Thus in 1950 to 1954 maternal deaths represented 6.5% of all deaths among women aged 15 to 44 while in 1975 to 1979 maternal deaths represented only 1.2%, a relative decrease of 81.5% (data not shown). This decrease occurred throughout the period among white and American In-
2.7 1.7
I
1970-1979
No. of deaths
Ratio
172 138 40 54
25.6 19.3 92.6 22.7
) No. of deaths
103 68 29 6
4.8 1.2
dian women; however, among black women, a slight increase occurred in the last 5 years of the study. The Oklahoma Maternal Mortality Committee assessed preventability and responsibility factors in 75.0% of the maternal deaths. Throughout the study period, preventable factors were identified for 66.9% of those evaluated. The number of maternal deaths that had preventable factors identified decreased from 105 in 1950 to 1954 to 25 in 197 4 to 1979, a relative decrease of 76.2% (Table IV), while the total number of maternal deaths decreased from 224 in 1950 to 1954 to 36 in 1974 to 1979, a relative decrease of 83.9%. The committee attempted to establish whether the primary responsibility for these maternal deaths was attributable to physician, patient, or both. They found that physicians were responsible for factors that could have been prevented in 52.1% of the assessed maternal deaths. Patients were responsible for factors that could have been prevented in 33.8% of the assessed deaths, and the physicians and patients combined were responsible for preventable factors in 11.7% of the maternal deaths. The percentage of maternal deaths with preventable factors that were the responsibility of the physician increased from 41.9% in 1950 to 72.2% in 1965, then declined to 40% in 1975 to 1979. In the same period,
1192 Moses et al.
November 1987 Am J Obstet Gynecol
Table III. Causes of maternal deaths by decade and race, Oklahoma, 1950 through 1979 (percentage distribution) All races
Cause
Total (1950-1979)
1950-1959
Hemorrhage Preeclampsia-eclampsia Complications of abortion Puerperal infection Ectopic pregnancy Amniotic fluid embolism Pulmonary embolism Complications of anesthesia Cardiovascular disorder Others Total No. of deaths
24.4 17.1 8.7 7.2 7.0 4.3 4.3 5.2 7.0 14.8 100.0 632
27.2 20.5 8.7 3.5 6.2 1.7 4.2 4.8 8.7 14.5 100.0 357
1
1960-1969
Race-specific (1950-1979) 1
1970-1979
White
18.5 12.6 7.8 15.5 11.7 5.8 1.9 4.9 3.9 17.4 100.0 103
24.9 15.3 8.1 7.4 5.2 5.2 5.7 4.4 7.6 16.2 100.0 406
22.1 12.8 9.3 9.9 5.8 8.7 5.8 6.4 5.2 14.0 100.0 172
I
Black
21.0 19.9 9.4 4.1 12.9 2.3 1.8 8.2 6.4 14.0 100.0 171
I
Indian
30.9 21.8 10.9 16.4 1.8 3.6 1.8 1.8 3.6 7.4 100.0 55
Table IV. Responsibility for preventable factors resulting in maternal deaths assessed by Maternal Mortality Committee, Oklahoma, 1950 through 1979 (percentage distribution) Years Responsibility
1950-1954
1955-1959
1960-1964
1965-1969
1970-1974
1975-1979
Physician Patient Physician and patient Other Total
41.9 40.0 15.2 2.9 100.0
50.4 34.0 2.4 3.2 100.0
59.6 25.4 12.8 2.2 100.0
72.2 16.7 11.1 0.0 100.0
61.5 28.2 5.2 5.1 100.0
40.0 56.0 4.0 0.0 100.0
Estimated No. of preventable deaths
105
65
47
36
39
25
the percentage of maternal deaths with preventable factors that were the responsibility of the patient decreased gradually from 40.0% in 1954 to 16.7% in 1965 to 1966, then climbed up to 56.0% in 1975 to 1979. Comment
The decline of maternal mortality in Oklahoma closely parallels that of the United States as a whole. Oklahoma's maternal mortality ratio, as calculated by the National Center for Health Statistics, was 85.21100,000 live births in 1950 and 10.11100,000 live births in 1979, a decrease of 88.2%. During the same period, U.S. maternal mortality ratios decreased by 90.6%. Studies in several states found that the incidence of maternal mortality was higher than that reported through the standard vital records reporting systems. 6 ' 9 The method of ascertaining maternal deaths through maternal mortality committee review may be more complete than using national vital statistics alone. 8 The rates observed in this study are higher than those obtained from the National Center for Health Statistics. These studies have underscored the importance of im-
proved surveillance in identifying maternal deaths. The maternal mortality committee is one way of clarifying the cause of maternal deaths. Many reported studies calculated the maternal mortality ratio with direct obstetric death as defined by the guidelines set by the AMA used as the numerator. 9 · 10 Rochat 12 emphasized that if pregnancy-related deaths were to be used as the numerator instead of direct obstetric deaths, the ratio may be twice as high as the current reported maternal mortality ratio. ICD-9-CM comes closer to measuring pregnancy-related deaths than the AMA classification or previous revisions of the lCD. For the 30-year period of this study, use of the ICD-9-CM classification resulted in 23.8% more deaths classified as maternal deaths when compared with those classified by the AMA's direct obstetric death classification. Smith et al. 13 classified all maternal deaths in the United States from 1974 to 1978 by using ICD-9-CM and ICDA-8 and found that the use of ICD-9-CM resulted in an increase of 8.8% over ICDA-8 in the number of deaths classified as maternal deaths. All maternal deaths identified in this study occurred less than 42
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days after delivery and met the ICD-9-CM definition of maternal death. The race-specific analysis revealed that among black and American Indian women, maternal mortality ratios are still higher than the ratio for white women. The risk of death from childbearing remained greater for black women, while for American Indian women, the risk of death due to pregnancy has decreased and is similar to that o£ white women. The improvement in the American Indian maternal mortality ratio in Oklahoma may reflect improvements in obstetric care, improvements in socio-economic status, or an artifactual difference in reporting racial status on birth or death certificates. The important observation from the perspective of health care services is that the difference between ratios for black women and those for white women did not decrease. In fact, this difference has increased in the last decade. This difference is due in part to the increased proportion of maternal deaths of black women that are due to ectopic pregnancy and preeclampsia-edam psia. The percentage of deaths due to maternal causes among black women of reproductive age was higher than the percentage of deaths due to maternal causes among American Indian and white women. Factors contributing to this elevated risk are that black teenagers have a higher fertility rate than white teenagers in Oklahoma 14 and that black women may wait until later in their pregnancies than American Indian or white women to seek prenatal and obstetric care. The study of Buehler et al. 15 revealed that black women aged 35 or older are at significantly higher risk of death than white women and their risk was even greater for deaths associated with abortive outcomes (including ectopic pregnancy). A significant finding was the higher rate of deaths in ectopic pregnancy among older black women. This reflects the fourfold higher rate of ectopic pregnancies among black women aged 35 and older compared with white women in the United States. One contributing factor to death from ectopic pregnancy is a failure to diagnose early pregnancy among women aged 35 and older. The diagnosis of ectopic pregnancy by physical examination is more difficult in these women because a greater proportion are overweight. 16 Progress has been made in reducing the number of maternal deaths in Oklahoma, especially those due to hemorrhage, preeclampsia-eclampsia, and complications of abortion. In 1965, Crosbt 7 reported that hemorrhage was the leading cause of maternal deaths, and a later study by Jimerson and Crosbt 8 showed that hemorrhage continued to be the leading cause of maternal death in Oklahoma. More recently, hemorrhage has dropped behind preeclampsia-eclampsia as the leading cause of maternal deaths.'" The number of maternal deaths due to preeclampsia-
Maternal mortality in Oklahoma, 1950-1979
1193
eclampsia fell precipitately between the 1950s and the 1960s. Tyler and Saeger2" reported that preeclampsiaeclampsia was the leading cause of pregnancy-related deaths among American Indian women in eastern Oklahoma in 1965. Vaughn 21 reported that 30% of total maternal deaths among American Indians in New Mexico were due to preeclampsia-eclampsia. Our study also showed a similar pattern among American Indians in Oklahoma. Pregnant American Indian women are two and a half times more likely to die of preeclampsiaeclampsia than are white women. Early identification of high-risk women may well prevent maternal mortality caused by preeclampsia-eclampsia. 2" Although complications of abortion were the third leading cause of maternal deaths in Oklahoma over the entire period, there were no deaths due to complications of induced abortion during the last 5 years. This may be due to widespread use of effective methods of contraception and to the availability of safe, legal abortion in Oklahoma. Among all maternal deaths, the percentage of women who were single has more than doubled in the 30-year period; this phenomenon is particularly notable among black women. These deaths may reflect the trend of more births occurring out of wedlock in recent years and the higher percentage of out-of-wedlock births among black teenage women than among American Indian or white women.'' Since preventable factors were identified in two thirds of the maternal deaths evaluated, maternal mortality in Oklahoma could be reduced to three deaths per 100,000 live births. However, achieving this residual reduction in mortality will require intensive efforts to understand the events leading to maternal death. Clinical data are particularly useful in determining the evaluation of events that led to the woman's death, but clinical data alone do not always provide adequate information to accurately classify the cause of death. Autopsies provide useful additional information. Although the proportion of maternal deaths evaluated with autopsies increased over the three decades studied, clinicians should continue to strive to obtain permission for autopsies to determine the specific pathologic causes of maternal death. Although the recent dramatic decrease in Oklahoma's maternal mortality is encouraging, continued effort in mortality surveillance and health education will be necessary to meet these objectives. REFERENCES L Marmo! JG, Scriggins AL, Vollman RF. History of the maternal mortality study committees in the United States. Obstet Gynecol 1969;34:123. 2. Committee on Maternal and Child Care of the Council on Medical Services. A guide for maternal death studies; American Medical Association. 3. World Health Organization. International classification of
Moses et al.
4. 5. 6.
7. 8.
9. 10.
11. 12. 13.
diseases. 9th rev. Clinical modification ICD:9. Washington DC: United States Department of Health and Human Services, 1979 vol 1:527. Daniel WW. Biostatistics: a foundation for analysis in health sciences. New York: John Wiley, 1974:368. Mausner JS, Bahn AK. Epidemiology: an introductory text. Philadelphia: WB Saunders, 1974:136. Rochat RW. The magnitude of maternal mortality: definitions and methods of measurement. In Candy U, Rafnam SS. Prevention and treatment of contraceptive failure. New York: Plenum Press, 1986:201-14. Ziskin LJ, Gregory M, Kreitzer M. Improved surveillance of maternal deaths. IntJ Gynaecol Obstet 1979;16:281. Speckhard ME, Comas- Urrutia AC, Rigan-PerezJG, Adamsons K. Intensive surveillance of pregnancy-related deaths, Puerto Rico, 1978-1979. Bol Asoc Med PR 1985;77:508. Rubin GL, McCarthy B, Shelton], Rochat R, Terry J. The risk of childbearing re-evaluated. Am J Public Health 1981;71:712. Schaffner W, Federspiel CF, Fulton ML, Gilbert DG, Stevenson LB. Maternal mortality in Michigan: an epidemiologic analysis, 1950-1971. Am J Public Health 1977; 67:821. Centers for Disease Control. Maternal mortality: pilot surveillance in seven states. MMWR 1985;34:709. Rochat R. Maternal mortality in the United States of America. World Health Stat 1981 ;34:2. Smith .JC, Hughes JM, Pekow PS, Rochat RW. An As-
November 1987 Am J Obstet Gynecol
14. 15. 16.
17. 18. 19. 20. 21. 22.
sessment of the incidence of maternal mortality in the US. Am J Public Health 1984;74:780. Fermo VA, DePersio SR, Lorenz D, Oberle M. Recent trends in pregnancy among teenagers in Oklahoma. J Okla State Med Assoc 1985;78:169. Buehler JW, Kaunitz AM, Hogue CJ, Hughes JM. Maternal mortality in women aged 35 years or older: United States. JAMA 1986;255:53. Forman MR, Trowbridge FL, Gentry EM, Marks JS, Hogelin GC. Overweight adults in the United States: the behavorial risk factor surveys. Am J Clin Nutr 1986; 49:410. Crosby WM. Hemorrhage as a cause of maternal mortality in Oklahoma. J Okla State Med Assoc 1965;58:490. Jimerson SD, Crosby WM. Maternal mortality in Oklahoma: hemorrhage remains a problem. Okla State Med Assoc 1978;71:197. Jennings R, Crosby W, DePersio S. Preeclampsiaeclampsia: the number one cause of maternal death in Oklahoma.] Okla State Med Assoc 1984;77:107. Tyler C, Saeger A. Maternal health and socioeconomic status of nonreservation Indians. Public Health Rep 1968;83:465. Vaughn B. Maternal deaths in New Mexico, 1956-1966. Rocky Mt Med J 1969;66:65. Kaunitz A, Hughes J, Grimes D, et al. Causes of maternal mortality in the United States. Obstet Gynecol 1985;65: 605.
Anorexia nervosa, bulimia, and pregnancy Donna E. Stewart, M.D., Joel Raskin, M.D., Paul E. Garfinkel, M.D., Ophelia L. MacDonald, M.D., and G. Edick Robinson, M.D. Toronto, Ontario, Canada Of 74 women previously treated for anorexia nervosa or bulimia, 15 had conceived 23 pregnancies when assessed at follow-up. The status of the eating disorder, course of pregnancy and delivery, infant health, and postpartum adjustment are described. Women in whom eating disorders were in remission at conception had greater maternal weight gain and babies with higher birth weights and 5-minute Apgar scores than women who conceived while they still had symptoms of restricting anorexia nervosa or bulimia. Women who had symptoms of eating disorders at conception also had continuance or worsening of these symptoms during pregnancy and the postpartum year. We recommend delay of pregnancy until the eating disorder is truly in remission. (AM J OssTET GvNECOL 1987;157:1194-8.)
Key words: Anorexia nervosa, bulimia, pregnancy, infants
From the Departments of Psychiatry and Obstetrics and Gynecology, University of Toronto, St. Michael's Hospital, and Toronto General Hospital. This work was supported in part by Grant No. 921 from the Ontario Mental Health Foundation to Dr. P. E. Garfinkel from 1985 to 1987. Presented in part to the Canadian Psychiatric Association Annual Meeting, Vancouver, British Columbia, Canada, September 1986, and to the American Society for Psychosomatic Obstetrics and Gynecology Annual Meeting, Point Clear, Alabama, March 25-29, 1987. Received for publication November 4, 1986; revised May 12, 1987; accepted july 14, 1987. Reprint requests: Dr. D. E. Stewart, St. Michael's Hospital, 30 Bond St., Floor 4M, Toronto, Ontario, Canada M5B 1W8.
1194
The high prevalence of anorexia nervosa and bulimia among young women,' combined with more effective treatment of these conditions, has resulted in more of these women eventually becoming pregnant. Little is known about the course of pregnancy in these women and even less is known about the health of their infants. Many psychological conflicts thought to be important in patients with eating disorders concerning adult sexuality, body image, autonomy, dependency, and relationships to parents are highlighted during normal pregnancy. This has led to speculation that pregnancy