Abortion Surveillance --- United States, 2000

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Laurie D. Elam-Evans, Ph.D.
Lilo T. Strauss, M.A.
Joy Herndon, M.S.
Wilda Y. Parker
Sonya V. Bowens, M.S.
Suzanne Zane, D.V.M.
Cynthia J. Berg, M.D.
Division of Reproductive Health
National Center for Chronic Disease Prevention and Health Promotion

Problem/Condition: CDC began abortion surveillance in 1969 to document the number and characteristics of women obtaining legal induced abortions.

Reporting Period Covered: This report summarizes and describes data reported to CDC regarding legal induced abortions obtained in the United States in 2000.

Description of System: For each year since 1969, CDC has compiled abortion data by state or area of occurrence. During 1973--1997, data were received from or estimated for 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City. In 1998 and 1999, CDC compiled abortion data from 48 reporting areas. Alaska, California, New Hampshire, and Oklahoma did not report, and data for these areas were not estimated. In 2000, Oklahoma again reported these data, increasing the number of reporting areas to 49.

Results: A total of 857,475 legal induced abortions were reported to CDC for 2000 from 49 reporting areas, representing a 0.5% decrease from the 861,789 legal induced abortions reported by 48 reporting areas for 1999 and a 1.3% decrease for the same 48 reporting areas that reported in 1999. The abortion ratio, defined as the number of abortions per 1,000 live births, was 246 in 2000 (for the same 48 reporting areas as 1999), compared with 256 reported for 1999. This represents a 3.8% decline in the abortion ratio. The abortion rate (for the same 48 reporting areas as 1999) was 16 per 1,000 women aged 15--44 years for 2000. This was also a 3.8% decrease from the rate reported for procedures performed during 1997--1999 for the same 48 reporting areas.

The highest percentages of reported abortions were for women aged <25 years (52%), women who were white (57%), and unmarried women (81%). Fifty-eight percent of all abortions for which gestational age was reported were performed at <8 weeks of gestation, and 88% were performed before 13 weeks. From 1992 (when detailed data regarding early abortions were first collected) through 2000, steady increases have occurred in the percentage of abortions performed at <6 weeks of gestation. Few abortions were performed after 15 weeks of gestation; 4.3% were obtained at 16--20 weeks and 1.4% were obtained at >21 weeks. A total of 31 reporting areas submitted data stating that they performed medical (nonsurgical) procedures, making up 1.0% of all reported procedures from the 42 areas with adequate reporting on type of procedure.

In 1998 and 1999 (the most recent years for which data are available), 14 women died as a result of complications from known legal induced abortion. Ten of these deaths occurred in 1998 and four occurred in 1999; no deaths were associated with known illegal abortion.

Interpretation: From 1990 through 1997, the number of legal induced abortions gradually declined. In 1998 and 1999, the number of abortions continued to decrease when comparing the same 48 reporting areas. In 2000, even with one additional reporting state, the number of abortions declined slightly. In 1998 and 1999, as in previous years, deaths related to legal induced abortions occurred rarely (<1 death per 100,000 abortions).

Public Health Action: Abortion surveillance in the United States continues to provide data necessary for examining trends in numbers and characteristics of women who obtain legal induced abortions and for increasing understanding of one additional aspect of the spectrum of pregnancy outcomes. Policy makers and program planners need these data to improve the health and well-being of women and infants.

Introduction

CDC began conducting abortion surveillance in 1969 to document the number and characteristics of women obtaining legal induced abortions and to monitor one outcome of unintended pregnancies. This report is based on abortion data for 2000 provided to CDC's National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Division of Reproductive Health.

Methods

For 2000, CDC compiled data that were voluntarily provided from 49 reporting areas in the United States: 47 states (excluding Alaska, California, and New Hampshire), the District of Columbia, and New York City. Legal induced abortion was defined as a procedure, performed by a licensed physician or someone acting under the supervision of a licensed physician, that was intended to terminate a suspected or known intrauterine pregnancy and to produce a nonviable fetus at any gestational age (1,2). The total number of legal induced abortions was available from all reporting areas; however, not all of these areas collected data regarding some or all of the characteristics of women who obtained abortions. Thus, the availability of data on characteristics of women obtaining an abortion varied by reporting area in 2000.

Most reporting areas (46 states, the District of Columbia, and New York City) collected and reported adequate data (i.e., data categorized in accordance with surveillance variables and with <15% unknown values) by age of the woman, whereas only 29 states, the District of Columbia, and New York City collected and reported adequate data by Hispanic ethnicity. Therefore, the findings in this report reflect characteristics of women only from reporting areas that submitted adequate data for the characteristics being examined. For the majority of state tables, the percentage data include a category for unknown values. However, for trend data, out-of-area residents, adolescent ages, and two-characteristics tables, percentages presented are based on known values only.

For the 49 reporting areas, data concerning the number of women obtaining legal induced abortions were provided by the central health agency.* These agencies provided data on numbers of abortions and characteristics of women obtaining abortions by the state in which the abortions were performed (i.e., state of occurrence). For most states, abortion totals were also available by the woman's state of residence. However, three states (Delaware, Maryland, and Wisconsin) reported characteristics only for women who were residents and who obtained abortions in the state, but not for women from out of state; and one state (Iowa) provided numbers and characteristics only for state residents. Two states (Florida and Louisiana) did not report abortion totals by resident status, and two states (Arizona and Massachusetts) provided only the total number of abortions for out-of-state residents without specifying individual states or areas of residence.

This report provides overall and state-specific abortion statistics. For all characteristics for which birth or population data were available, abortion ratios (number of abortions per 1,000 live births) or abortion rates (number of abortions per 1,000 women in a given age group) are provided. Starting with 1996, abortion ratios were calculated by using the number of live births to residents of each area, from birth data reported to CDC's National Center for Health Statistics (NCHS); numbers had previously been received from state health departments. The population data used for calculating abortion rates had previously been obtained from the U.S. Census Bureau postcensual data. However, because of the impact of changes in Office of Management and Budget (OMB) standards in 1997 that allowed for multiple race selections on the 2000 Census, no population data were released by the Census Bureau. NCHS bridged race and ethnicity data were used for calculating abortion rates; this involves a model that translates multiple race responses for an individual into the one, single response that the model predicts the individual most likely would have reported under the 1977 OMB standards (3).

Women who obtained legal induced abortions were categorized by 5-year age groups and by single years of age for adolescents aged 15--19 years. Abortion numbers, ratios and rates are presented by age group. Because nearly all (94%) abortions among women aged <15 years occurred among those aged 13--14 years in 1988 (the latest year for which this information is known) (4), the population of women aged 13--14 years was used as the denominator for calculating abortion rates for women <15 years. Rates for women aged >40 years were based on the number of women aged 40--44 years. Rates for all women who obtained abortions, however, were based on the population of women aged 15--44 years.

Race was categorized by three groups: white, black, and other races. Other races included Asian/Pacific Islander, American Indian, Alaska Native, and women classified as "other" race. Ethnicity was categorized as Hispanic and non-Hispanic. As in previous reports, race and ethnicity were provided as separate characteristics and abortions were not cross-classified by race and ethnicity. Abortion numbers, ratios and rates are presented by race and by ethnicity.

Marital status was reported as either married (including women who were married or separated) or unmarried (including those who were never married, divorced, or widowed). Abortion numbers and ratios are presented by marital status.

Gestational age (in weeks) at the time of abortion was categorized as <6, 7, 8 and <8, 9--10, 11--12, 13--15, 16--20, and >21. Weeks of gestation were estimated in 20 reporting areas as the time elapsed since the woman's last menstrual period. For 17 other states, gestational age was reported based on the physician's estimate (data from the clinical examination including ultrasound results). For the remaining six states, gestational age came from a combination of physician's estimates and the time elapsed since the woman's last menstrual period. Most areas (41 of 43) that reported adequate data on weeks of gestation at the time of abortion also reported abortions performed at <8 weeks separately for <6, 7, and 8 weeks of gestation. Abortion numbers are presented by gestational age.

CDC has periodically reported data on abortion-related deaths since these deaths were first included in the Abortion Surveillance Report in 1972 (5,6). An abortion-related death was defined as a death resulting from 1) a direct complication of an abortion, 2) an indirect complication caused by the chain of events initiated by abortion, or 3) aggravation of a preexisting condition by the physiologic or psychologic effects of the abortion (1,2). Sources of data for abortion-related deaths included national and state vital records, maternal mortality review committees, surveys, private citizens and groups, media reports, health-care providers, medical examiners' reports, and computerized searches of full-text newspaper databases. All deaths associated with any type of abortion, induced or spontaneous, were investigated. For each death possibly related to an induced abortion or an abortion of unknown type, clinical records and autopsy reports were requested and reviewed by two clinically experienced medical epidemiologists to determine the cause of death and whether the death was abortion related. Each abortion-related death was then categorized as legal induced, illegal induced, spontaneous, or unknown (whether induced or spontaneous). Abortion-related deaths for 1972--1999 are provided in this report. Abortion mortality data are updated whenever additional information is supplied to CDC. The 1999 data have not been published previously and are the most recent data available. National case-fatality rates were calculated as the number of known legal induced abortion-related deaths per 100,000 reported legal induced abortions. Case-fatality rates for 1972--1997 are provided in this report. Case-fatality rates for 1998--1999 cannot be calculated because a substantial number of abortions occurred in the four nonreporting states, and the total number of abortions (the denominator) is unknown.

Results

Overall, the annual number of legal induced abortions in the United States increased gradually until it peaked in 1990, and it has declined in most years thereafter (Figure 1). In 2000, a total of 857,475 legal induced abortions were reported to CDC by 49 reporting areas. This represents a 0.5% decrease from 1999, for which 861,789 legal induced abortions were reported from 48 reporting areas (Table 1) and a 1.3% decrease in the same 48 reporting areas as 1999 (Table 2).

The national legal induced abortion ratio increased from 196 per 1,000 live births in 1973 (the first year that 52 areas reported) to 358 per 1,000 live births in 1979 and remained nearly stable through 1981 (Figure 1) (Table 2). The ratio peaked at 364 per 1,000 live births in 1984 and since then has shown a nearly steady decline. In 2000, the abortion ratio was 245 per 1,000 live births in 49 reporting areas and 246 for the same 48 reporting areas available for 1999. This represents a 3.8% decrease from 1999 (256 per 1,000 live births) for the 48 reporting areas (Table 2) (6).

The national legal induced abortion rate increased from 14 abortions per 1,000 women aged 15--44 years in 1973 to 25 per 1,000 in 1980. In the 1980s and early 1990s, the rate remained stable at 23--24 abortions per 1,000 women aged 15--44 years, and during 1994--1997 it again stabilized at 20--21. The abortion rate remained unchanged at 17 per 1,000 women aged 15--44 years from 1997 through 1999 in the same 48 reporting areas. In 2000, the abortion rate declined to 16 per 1,000 women aged 15--44 years (overall and in the same 48 reporting areas as 1999).

The numbers, ratios, and rates of reported legal induced abortions are presented by area of residence as well as by area of occurrence (Table 3). In 2000, the highest numbers of reported legal induced abortions occurred in New York City (94,466), Florida (88,563), and Texas (76,121); the fewest^† occurred in Idaho (801), South Dakota (878), and North Dakota (1,341) (Table 3). The abortion ratios by state or area of occurrence ranged from 39 per 1,000 live births in Idaho to 869 per 1,000 live births in the District of Columbia. The rates by occurrence ranged from 3 per 1,000 women aged 15--44 years in Idaho to 46 per 1,000 women aged 15--44 years in the District of Columbia. These ratios and rates should be viewed with consideration of the sizable variation by state in the percentage of abortions obtained by out-of-state residents. In 2000, approximately 9% of reported abortions were obtained by out-of-state residents. The percentages ranged from 0.4% in Hawaii to 56% in the District of Columbia (Table 3). Data by state of residence are incomplete because three states (Alaska, California, and New Hampshire) did not report and five states (Arizona, Florida, Iowa, Louisiana, and Massachusetts) did not provide any data concerning the residence status of all women obtaining abortions in their state.

Women aged 20--24 years were known to have obtained 33% of all abortions for which age was adequately reported. Women aged <15 years were known to have obtained <1.0% of all abortions in areas where age was reported (Table 4). Abortion ratios were highest for the youngest women (708 abortions per 1,000 live births for women aged <15 years) and lowest for women aged 30--34 years (145 per 1,000 live births) (Figure 2) (Table 4). In contrast to abortion ratios, among women for whom age was reported, abortion rates were highest for women aged 20--24 years (33 abortions per 1,000 women) and lowest for women at the extremes of reproductive age (2 abortions per 1,000 women aged 13--14 years and 2 per 1,000 women aged 40--44 years) (Table 4). Among adolescents (aged <20 years), the percentage of abortions obtained increased with increasing age. However, the abortion ratio was highest for those <15 years (701 abortions per 1,000 live births)^§ and lowest for those aged 19 years (324 per 1,000 live births) (Table 5). Conversely, the rates of abortions were lowest for adolescents aged <15 years (2 per 1,000 women aged 13--14 years) and highest for women age 19 (29 per 1,000 women aged 19 years) (Table 5).

Abortion trends by age indicate that since 1973, abortion ratios for women aged <15 years have been higher than for any other age group (Figure 3). For women aged <19 years and those aged >40 years, the abortion ratio increased overall from 1974 through the early 1980s and declined thereafter (Figure 3). The abortion ratio for women aged 20--34 years (the groups with the highest fertility rates) (7) has remained essentially stable since the mid-1980s. The abortion ratio for women aged 35--39 years has gradually declined over time.

In 2000, for women whose weeks of gestation at the time of abortion were adequately reported, 57% of reported legal induced abortions were known to have been obtained at <8 weeks of gestation, and 87% at <13 weeks (Table 6). Overall, 23% of abortions were known to have been performed at <6 weeks of gestation, 18% at 7 weeks, and 17% at 8 weeks (Table 7). Few reported abortions occurred after 15 weeks of gestation; 4.3% were at 16--20 weeks, and 1.4% were at >21 weeks.

For women whose type of procedure was adequately reported, almost all (97%) abortions were known to have been performed by curettage and 0.4% by intrauterine instillation (Table 8). Hysterectomy and hysterotomy were included in the "other" procedure category and were known to have been used in fewer than 0.01% of all abortions. Thirty-one reporting areas submitted data stating that they performed medical (nonsurgical) procedures,^¶ hereafter referred to as medical abortions. Medical abortions make up approximately 1% of all procedures reported from the 42 areas with adequate reporting on type of procedure. However, three areas included medical abortions in the "other" category because data for medical abortions are not collected as a separate category on their abortion reporting form. For 2000, a total of 6,895 medical abortion procedures were submitted by the 28 reporting areas that reported medical abortions separately. This reflects an increase of 10% from the 6,278 medical abortions reported by 26 reporting areas for 1999 (6). We do not know to what extent the 6,895 medical abortions reported to CDC for 2000 represent the use of this procedure in all reporting areas.

In the 41 areas for which race was adequately reported, approximately 55% of women who obtained legal induced abortions were known to be white, 35% were black, and 7% were of other races; for 3% of the women, race was unknown. (Table 9). The abortion ratio for black women (503 per 1,000 live births) was 3.0 times the ratio for white women (167 per 1,000 live births). Additionally, the abortion ratio for women of other races (329 per 1,000 live births) was 2.0 times the ratio for white women. The abortion rate for black women (30 per 1,000 women) was 3.1 times the rate for white women (10 per 1,000 women), whereas the abortion rate for women of other races (22 per 1,000 women) was 2.2 times the rate for white women.

Twenty-nine states, the District of Columbia, and New York City reported adequate data** concerning the ethnicity of women who obtained legal induced abortions (Table 10). The percentage of abortions known to have been obtained by Hispanic women in these reporting areas was 17% overall and ranged from <0.1% in Kentucky to 46% in New Mexico. For Hispanic women in these reporting areas, the abortion ratio was 225 per 1,000 live births. The abortion rate for Hispanic women was 16 abortions per 1,000 women.

For women whose marital status was adequately reported, 78% of women who obtained abortions were known to be unmarried (Table 11). The abortion ratio for unmarried women was 8.8 times the ratio for married women (570 versus 65 abortions per 1,000 live births).

For women for whom data on previous live births was adequately reported, 39% of women who obtained legal induced abortions were known to have had no previous live births, and 86% had had two or fewer previous live births (Table 12). The abortion ratio was highest for women who had three previous live births (285 per 1,000 live births) and lowest for women who had one previous live birth (194 per 1,000 live births).

In 2000, of women who obtained an abortion and whose number of previous abortions was adequately reported, 53% were reported to have obtained an abortion for the first time. Eighteen percent of women were reported to have had two or more previous abortions (Table 13).

For women whose age and race were known, white women had a slightly greater percentage of abortions in the youngest (<19 years) and oldest (>35 years) age groups compared with women of black or other races (19% versus 17% and 12% versus 10%, respectively) (Table 14). For women whose marital status and race were both known, the percentage of reported abortions among black or other races that were obtained by unmarried women (84%) was higher than that obtained by unmarried white women (79%). Among women obtaining abortions whose age and Hispanic ethnicity were known and reported adequately (29 reporting areas) the percentage of abortions obtained by older women (>35 years) of non-Hispanic ethnicity (12%) was greater than that for older women of Hispanic ethnicity (9%)(Table 15). For women whose marital status and ethnicity were known and reported adequately (27 reporting areas), the percentage of reported abortions obtained by unmarried women was somewhat higher for non-Hispanic compared to Hispanic women (82% versus 80%) (Table 15). Data were not available to cross-classify race by Hispanic ethnicity.

As in the past, approximately 88% of all abortions (for which gestational age at the time of abortion was reported adequately) were obtained during the first 12 weeks of gestation (Table 1). The percentage of women who obtained an abortion at <8 weeks of gestation increased with age, with the exception of women aged 35--39 years (Figure 4) (Table 16). This association is most pronounced for abortions obtained at <6 weeks' gestation (Table 17). The percentage of women who obtained an abortion at >21 weeks of gestation decreased with age for women through 25--29 years (Table 16). Among women with adequately reported race and weeks of gestation, white women and women of other races were more likely than black women to obtain abortions at <6 or 7 weeks of gestation (Table 17). Among women with adequately reported known ethnicity and weeks of gestation, 25% of Hispanic women obtained abortions at <6 weeks of gestation and 59% obtained abortions at <8 weeks' gestation. This is slightly more than the 57% of non-Hispanic women who obtained abortions at <8 weeks' gestation (Table 17).

For women whose type of procedure and weeks of gestation were adequately reported, approximately 99% of reported abortions obtained at <15 weeks of gestation were performed by using curettage (primarily suction procedures) (Table 18). Approximately 88% of the 6,229 reported medical abortions were performed at <8 weeks' gestation, representing 1.6% of all abortions that were performed at <8 weeks' gestation. At >16 weeks of gestation, medical abortions (n = 559) also made up 1.6% of all abortions. Medical abortions constituted <0.1% of procedures performed in the 9--15-weeks gestation range. Intrauterine instillation involved the use of saline or prostaglandin and was used rarely (0.3% of all abortions), primarily at >16 weeks of gestation.

From the National Pregnancy Mortality Surveillance System, CDC identified 22 maternal deaths for 1998 and 17 maternal deaths for 1999 that were thought to be potentially related to abortion. These maternal deaths were identified either by some indication of abortion on the death certificate or from information such as a news report associated with the death. Investigation of these cases showed that 10 of the 22 deaths in 1998 and four of the 17 deaths in 1999 were related to legal induced abortion and none to illegal induced abortion (Table 19). For 1998, 11 deaths were due to spontaneous abortion, and one death was found not to be abortion related. For 1999, 10 deaths were due to spontaneous abortion, and three deaths were found not to be abortion related. Numbers of deaths due to legal induced abortion were highest before the 1980s, with very few deaths occurring in 1999 (Table 19). Possible abortion-related deaths that occurred during 2000--2002 are currently being investigated.

Discussion

A total of 857,475 legal induced abortions were reported for 2000 in the United States from 47 states, the District of Columbia, and New York City. This is a decline of 0.5% from the legal induced abortions reported for 1999 from 48 reporting areas (6). A decline of 1.3% in the number of abortions is seen when the same 48 reporting areas from 1999 are compared with those for 2000 (6). Before 1998, a substantial number of legal induced abortions were estimated to have been performed in California (e.g., >23% of the U.S. total in 1997) (8). Beginning in 1998, data were no longer estimated for nonreporting states. The lack of data for California for 2000 explains most of the 28% decrease from the annual number of abortions reported in 1997 (8) as well as a portion of the decrease in the total ratio and rate.

Overall, abortion ratios and abortion rates have declined over time (Figure 1). The abortion ratio for 2000 (246 per 1,000 live births for the same 48 reporting areas as 1999) was a 3.8% decline from the previous year. The abortion rate (16 per 1,000 women aged 15--44 years for the same 48 reporting areas as 1999) was also a decline of 3.8% from the rate reported in 1999 (Table 2). The overall declines in the abortion ratio and rate over time may reflect multiple factors, including a decrease in the number of unintended pregnancies (9); a shift in the age distribution of women toward the older and less fertile ages (7); reduced or limited access to abortion services, including the passage of abortion laws that affect adolescents (e.g., parental consent or notification laws and mandatory waiting periods) (10--14); and changes in contraceptive practices, including an increased use of contraception, such as condoms, and, among young women, of long-acting hormonal contraceptive methods that were introduced in the early 1990s (15--18).

The abortion rate reported here for the United States was higher than recent rates reported for Canada and Western European countries and lower than rates reported for China, Cuba, most Eastern European countries, and several of the Newly Independent States of the former Soviet Union (19,20).

As in previous years, the abortion ratio in 2000 varied substantially by age. Although the abortion ratio was highest for adolescents in 2000, the ratio has gradually declined for women aged <15 and 15--19 years since the mid 1980s (Figure 3). Other studies also have indicated a decrease in birth rates for women aged 15--19 years during 1991--2000 and a decrease in adolescent pregnancy rates 1991--1997 (7,21--26).

The percentage distribution of abortions by known weeks of gestation has shifted slightly since the late 1970s. From 1992 (when detailed data on early abortions were first available) through 2000, data have indicated steady increases in procedures performed at <6 weeks' gestation with decreases occurring in the percentage of abortions performed at 8, 9--10, and 11--12 weeks' gestation. The increase in the percentage of abortions known to have been performed at <6 weeks may be related to an increase in availability of early abortion services since 1992 as well as to an increase in medical and surgical procedures that can be performed early in gestation (27,28). Abortions performed early in pregnancy are associated with lower risks of mortality and morbidity (29). The proportions of abortions performed later in pregnancy (>13 weeks) have varied very little since 1992. The gestational age at which an abortion is obtained can be influenced by several factors in addition to those for which surveillance data are available (age of the woman, race, marital status). These additional factors include level of education, availability and accessibility of abortion services, timing of confirmation of pregnancy, timing of personal decision-making, timing of prenatal diagnosis, level of fear of discovery of pregnancy, and denial of the pregnancy (30--32).

Since the mid-1990s, two medical regimens --- methotrexate and mifepristone, each used in conjunction with misoprostol --- have been tested in clinical trials and used by clinical practitioners to perform early medical abortions (28,33). CDC surveillance data indicate that >50% of all U.S. abortions are performed at <8 weeks of gestation, which is the timing of the regimen approved for both mifepristone and methotrexate (34). The medical procedures reported most often for abortions performed early in gestation (<7 weeks) are use of methotrexate with misoprostol and mifepristone with misoprostol (35,36). Mifepristone for medical abortion was approved by the Food and Drug Administration (FDA) for use and distribution in the United States in September 2000. This approval might result in early medical abortions becoming more widespread (37,38). The FDA-approved protocol can be initiated up to 49 days of gestation and requires three office visits by the patient: administration of oral mifepristone, administration 48 hours later of oral misoprostol in the health care provider's office, and a follow-up visit in approximately 14 days. Clinical studies of alternative medical abortion regimens have been performed in various countries and are ongoing (39--46).

In 1997, the U.S. Standard Report of Induced Termination of Pregnancy, published by the National Center for Health Statistics (NCHS) and used by providers for abortion reporting to state health departments, was revised to include a category for "medical (nonsurgical)" procedures (47). Medical abortion procedures have been included in this report since then as a separate category. CDC will continue to monitor early medical procedures and to report the number of these procedures (Table 8).

The percentage of abortions known to be performed by curettage (which includes dilatation and evacuation [D&E]) increased from 88% in 1973 to 98% in 2000 (Table 1), while the percentage of abortions performed by intrauterine instillation declined sharply, from 10% to 0.4%. The increase in use of D&E is likely due to the lower risk for complications associated with the procedure (48,49). The percentage of abortions performed by D&E (curettage) at >13 weeks' gestation increased from 31% in 1974 (the first year for which these data were available) to 96% in 2000; the percentage of abortions performed by intrauterine instillation at >13 weeks' gestation decreased from 57% to 1.7% (Table 18)(50).

The differential between the abortion ratio for black women and that for white women has increased from 2.0 in 1989 (the first year for which black and other races were reported separately) to 3.0 in 2000 (51). In addition, the abortion rate for black women has been approximately 3 times as high as that for white women (range: 2.6--3.1) since 1991 (the first year for which rates by race were published) (52). These rates by race are substantially lower than rates previously published by NCHS and suggest that the reporting areas for the 2000 report might not be fully representative of the U.S. black female population of reproductive age. Census Bureau estimates and birth certificate data indicate that the large majority of Hispanic women report themselves as white (7). Therefore, data for some white women actually represent Hispanic women.

In 2000, 41 states, the District of Columbia and New York City reported Hispanic ethnicity of women who obtained abortions. Because of concerns regarding the completeness of such data (>15% unknown data) in certain states, in 2000, data from only 29 states, the District of Columbia, and New York City were used to determine the number and percentage of abortions obtained by women of Hispanic ethnicity. These geographic areas represent approximately 46% of all reproductive-age Hispanic women in the United States for 2000 and approximately 47% of U.S. Hispanic births (53). Thus, the number of Hispanic women who obtain abortions is underestimated, and the number, ratio, and rate of abortions for Hispanic women in this report are not generalizable to the overall Hispanic population in the United States.

The abortion ratio for Hispanic women (225 per 1,000 live births) was lower than the ratio for non-Hispanic women (233 per 1,000 live births). This differs from the findings for abortions performed in 1999 and reflects a return to the previously observed pattern among Hispanic women of slightly lower or similar ratios to those for non-Hispanic women. As in the past, the abortion rate per 1,000 Hispanic women (16) was higher than the rate per 1,000 non-Hispanic women (13). This finding is consistent with another study (18) but differs substantially from abortion rates by ethnicity that were published previously by NCHS (25). The differences are likely due to the method used to account for underreporting of abortions by adjusting CDC tabulations to national totals. This finding also suggests that the reporting areas for the 2000 report are not fully representative of the U.S. Hispanic female population of reproductive age. Race-specific and ethnicity-specific differences in legal induced abortion ratios and rates might reflect differences among groups in factors such as socioeconomic status, access to family planning and contraceptive services, contraceptive use, and incidence of unintended pregnancies.

NCHS vital statistics reports indicate that fertility and live birth rates were substantially higher for Hispanic women as a whole than for non-Hispanic women for all age groups in 2000 (7). However, because fertility and live birth rates differ substantially among the Hispanic subgroups (Mexican, Puerto Rican, Cuban, other Hispanic), and these differ substantially from rates among the non-Hispanic subgroups (white, black, other), comparisons between Hispanic and non-Hispanic groups are of limited value (7). Currently available abortion surveillance data do not permit cross-classification of race by Hispanic ethnicity. Efforts are under way to provide a cross-classification of race and ethnicity in future reports to comply with OMB Directive 15, which specifies federal standards for the collection of data on race and ethnicity (54).

Compared with 1972, the annual number of deaths associated with known legal induced abortion in the late 1990s has decreased by approximately 70% (Table 19). In 1972, 24 women died from causes known to be associated with legal abortions and 39 died as a result of known illegal abortions. In 1999, four died as a result of legal induced abortion and none died as a result of illegal induced abortion. Numbers of legal, induced abortion-related deaths for 1998 and 1999, identified for all 52 reporting areas, are similar to those reported over the previous 18 years. However, national case-fatality rates for 1998 and 1999 cannot be calculated because a substantial number of abortions occurred in four nonreporting states, and the total number of abortions (the denominator) is unknown.

Because these data are reported voluntarily, several limitations exist. First, abortion data are compiled and reported to CDC by reporting area where the abortion was performed rather than by where the woman resides. This inflates the numbers, ratios, and rates of abortions for areas where a high proportion of legal abortions are obtained by out-of-state residents and undercounts procedures for states with limited abortion services or more stringent legal requirements for obtaining an abortion (causing women to seek abortions elsewhere). Second, four states (Alaska, California, New Hampshire, and Oklahoma) did not collect or report abortion data in 1998--1999 and three states (Alaska, California, and New Hampshire) did not report in 2000. Data for California and Oklahoma had been estimated before 1998; however, data for nonreporting states have not been estimated since 1997. Third, data provided to state or area health departments by providers might be incomplete (55). Fourth, the overall number, ratio, and rate of abortions are conservative estimates because the total numbers of legal induced abortions provided by central health agencies and reported to CDC for 2000 were probably lower than the numbers actually performed. Additionally, abortion totals for 2000 provided to CDC by central health agencies are 20% lower than that reported for 2000 for the same reporting areas by The Alan Guttmacher Institute, a private organization that contacts abortion providers directly (56). A previous report documented a discrepancy of approximately 12% (57); the reasons for this larger discrepancy are unclear. Fifth, not all states collected or reported data for all characteristics (e.g., age, race, and weeks of gestation) of women obtaining a legal induced abortion in 2000. Thus, the numbers, rates, and ratios derived in this analysis might not be representative of all women who obtained abortions.

Despite these limitations, findings from ongoing national surveillance of legal induced abortion are useful for several purposes. First, public health agencies use data from abortion surveillance to identify characteristics of women who are at high risk for unintended pregnancy. Second, ongoing annual surveillance is used to monitor trends in the number, ratio, and rate of abortions in the United States. Third, statistics regarding the number of pregnancies ending in abortion are used in conjunction with birth data and fetal death computations to estimate pregnancy rates (e.g., pregnancy rates among adolescents) (21--25). Fourth, abortion and pregnancy rates can be used to evaluate the effectiveness of family planning programs and programs for preventing unintended pregnancy. Fifth, ongoing surveillance provides data for assessing changes in clinical practice patterns related to abortion (e.g., longitudinal changes in the types of procedures and trends in weeks of gestation at the time of abortion). Finally, numbers of abortions are used as the denominator in calculating abortion mortality rates (29).

The Health Insurance Portability and Accountability Act (HIPAA) of 1996 was legislated to facilitate the electronic transfer of health data relating mostly to insurance coverage and transferability (58). Congress incorporated into HIPAA provisions that mandated adoption of federal privacy protections for certain individually identifiable health information, and the U.S. Department of Health and Human Services issued the Privacy Rule with April 14, 2003, as the date for implementation. The Privacy Rule states that protected health information for public health purposes is exempt from the Privacy Rule and, thus, covered entities may provide protected health information, without individual authorizations, to a public health authority, such as CDC, whose stated purpose is to prevent and control disease. Collection of surveillance data for this report is exempt from the Privacy Rule. However, the complexity of the rule might result in difficulty in its interpretation and therefore in collecting surveillance data on the part of certain contributing agencies (58).

Induced abortions usually result from unintended pregnancies, which often occur despite the use of contraception (15,59,60). Research has indicated that approximately 49% of all pregnancies in 1994 were unintended at conception (61). Additionally, 31% of births in 1995 were reported as unintended at conception; 21% were considered mistimed and 10% were considered unwanted (9,61). Unintended pregnancy is a problem not just for adolescents, unmarried women, or poor women; it is a pervasive public health problem for all women of reproductive age (9,15,52,61).

A reduction in unintended pregnancy, and thus abortion, will require several complex strategies. In a study of abortion patients conducted during 2000--2001, 54% of patients reported that they were using contraception during the month they became pregnant. However, their use of contraception might have been inconsistent or incorrect (18). In 1995, when the most recent NSFG was conducted, approximately 29% of sexually active U.S. women who used only oral contraceptives for birth control reported that they missed a birth-control pill one or more times during the 3 months before their NSFG interview. In addition, approximately 33% of U.S. women who were using only coitus-dependent contraceptive methods^†† during the 3 months before the interview used these methods inconsistently (9). Not all health insurance plans provide contraceptive benefits (62). Therefore, education regarding abstinence, contraceptive use and practices as well as access to and education regarding safe, effective, and affordable contraception and family-planning services might help reduce the incidence of unintended pregnancy and, therefore, the number of legal induced abortions in the United States (63--65).

Copies of this and other MMWR reports containing statistical and epidemiologic data about abortions can be obtained through the CDC website at http://www.cdc.gov/nccdphp/drh/surv_abort.htm.

The authors thank Elizabeth Fitch, Division of Reproductive Health, NCCDPHP, CDC, for her work on graphics, and Stephanie Ventura, Division of Vital Statistics, NCHS, CDC, for her review of this surveillance report.

References

^††Coitus-dependent contraceptive methods include male or female condoms, diaphragm, sponge, cream, jelly, or other methods that must be used at the time intercourse occurs.

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