Abortion Surveillance --- United States, 2008

Karen Pazol, PhD

Suzanne B. Zane, DVM

Wilda Y. Parker, MPH

Laura R. Hall, MPH

Cynthia Berg, MD

Douglas A. Cook, MBIS

Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC

Abstract

Problem/Condition: Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States.

Reporting Period Covered: 1999--2008.

Description of System: Each year, CDC requests abortion data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City). This information is provided voluntarily. For 2008, data were received from 49 reporting areas. For the purpose of trend analysis, data were evaluated from the 45 areas that reported data every year during 1999--2008. Abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births) were calculated using census and natality data, respectively.

Results: A total of 825,564 abortions were reported to CDC for 2008. Of these, 808,528 abortions (97.9% of the total) were from the 45 reporting areas that provided data every year during 1999--2008. Among these same 45 reporting areas, the abortion rate for 2008 was 16.0 abortions per 1,000 women aged 15--44 years, and the abortion ratio was 234 abortions per 1,000 live births. Compared with 2007, the total number and rate of reported abortions for these 45 reporting areas essentially were unchanged, although the abortion ratio was 1% higher. Reported abortion numbers, rates, and ratios remained 3%, 4%, and 10% lower, respectively, in 2008 than they had been in 1999.

Women aged 20--29 years accounted for 57.1% of all abortions reported in 2008 and for the majority of abortions during the entire period of analysis (1999--2008). In 2008, women aged 20--29 years also had the highest abortion rates (29.6 abortions per 1,000 women aged 20--24 years and 21.6 abortions per 1,000 women aged 25--29 years). Adolescents aged 15--19 years accounted for 16.2% of all abortions in 2008 and had an abortion rate of 14.3 abortions per 1,000 adolescents aged 15--19 years; women aged ≥35 years accounted for a smaller percentage (11.9%) of abortions and had lower abortion rates (7.8 abortions per 1,000 women aged 35--39 years and 2.7 abortions per 1,000 women aged ≥40 years). Throughout the period of analysis, abortion rates decreased among adolescents aged ≤19 years, whereas they increased among women aged ≥35 years. Among women aged 20--24 years abortion rates decreased during 1999--2003 and then leveled off during 2004--2008.

In contrast to the percentage distribution of abortions and abortion rates by age, abortion ratios in 2008 and throughout the entire period of analysis were highest among adolescents aged ≤19 years and lowest among women aged 30--39 years. Abortion ratios decreased during 1999--2008 for women in all age groups except for those aged <15 years; however, the steady decrease was interrupted from 2007 to 2008 when abortion ratios increased among women in all age groups except for those aged ≥40 years.

In 2008, most (62.8%) abortions were performed at ≤8 weeks' gestation, and 91.4% were performed at ≤13 weeks' gestation. Few abortions (7.3%) were performed at 14--20 weeks' gestation, and even fewer (1.3%) were performed at ≥21 weeks' gestation. During 1999--2008, the percentage of abortions performed at ≤13 weeks' gestation remained stable, whereas abortions performed at ≥16 weeks' gestation decreased 13%--17%. Moreover, among the abortions performed at ≤13 weeks' gestation, the distribution shifted toward earlier gestational ages, with the percentage of abortions performed at ≤6 weeks' gestation increasing 53%.

In 2008, 75.9% of abortions were performed by curettage at ≤13 weeks' gestation, and 14.6% were performed by early medical abortion (a nonsurgical abortion at ≤8 weeks' gestation); 8.5% of abortions were performed by curettage at >13 weeks' gestation. Among the 62.8% of abortions that were performed at ≤8 weeks' gestation and thus were eligible for early medical abortion, 22.5% were completed by this method. The use of medical abortion increased 17% from 2007 to 2008.

Deaths of women associated with complications from abortions for 2008 are being investigated under CDC's Pregnancy Mortality Surveillance System. In 2007, the most recent year for which data were available, six women were reported to have died as a result of complications from known legal induced abortions. No reported deaths were associated with known illegal induced abortions.

Interpretation: Among the 45 areas that reported data every year during 1999--2008, the total number and rate of reported abortions essentially did not change from 2007 to 2008. This finding is consistent with the recent leveling off from steady decreases that had been observed in the past. In contrast, the abortion ratio increased from 2007 to 2008 after having decreased steadily. In 2007, as in previous years, reported deaths related to abortion were rare.

Public Health Action: This report provides the data for examining trends in the number and characteristics of women obtaining abortions. This information is needed to better understand the reasons why efforts to reduced unintended pregnancy have stalled and can be used by policymakers and program planners to guide and evaluate efforts to prevent unintended pregnancy.

Introduction

This report is based on abortion data for 2008 that were provided voluntarily to CDC by the central health agencies of 49 reporting areas (the District of Columbia; New York City; and 47 states, excluding California, Maryland, and New Hampshire). Since 1969, CDC has conducted abortion surveillance to document the number and characteristics of women obtaining legal induced abortions in the United States (1). Following nationwide legalization of abortion in 1973, the total number, rate (number of abortions per 1,000 women aged 15--44 years), and ratio (number of abortions per 1,000 live births) of reported abortions increased rapidly, reaching their highest levels in the 1980s before decreasing at a slow yet steady pace (2--6). However, the incidence of abortion has varied considerably across demographic subpopulations (7--11), and recent reports suggest that the sustained pattern of decrease has leveled off (12--14). Continued surveillance is needed to monitor long-term changes in the overall incidence of abortion and to guide and evaluate programs for preventing unintended pregnancy in the United States.

Methods

Description of the Surveillance System

Each year, CDC requests tabulated data from the central health agencies of 52 reporting areas (the 50 states, the District of Columbia, and New York City) to document the number and characteristics of women obtaining abortions in the United States. For the purpose of surveillance, a legal induced abortion* is defined as an intervention performed by a licensed clinician (e.g., a physician, nurse-midwife, nurse practitioner, or physician assistant) that is intended to terminate a suspected or known ongoing intrauterine pregnancy and produce a nonviable fetus at any gestational age.

In most states, collection of abortion data is facilitated by the legal requirement for hospitals, facilities, and physicians to report abortions to a central health agency (15). These central health agencies voluntarily provide CDC aggregate numbers for the abortion data they have collected (16).

Although reporting to CDC is voluntary, most reporting areas do provide aggregate abortion numbers: during 1999--2008, a total of 45 reporting areas provided CDC a continuous annual record of abortion numbers,† and in 2008, CDC obtained aggregate abortion numbers from 49 reporting areas (excludes California, Maryland, and New Hampshire). However, the level of detail that CDC receives on the characteristics of women obtaining abortions varies considerably from year to year and among reporting areas. To encourage more uniform collection of these details, CDC has developed a model reporting form to serve as a technical guide (17). However, because the collection of abortion data is not federally mandated, reporting areas can develop their own forms and do not necessarily collect all the information that CDC compiles.

Variables and Categorization of Data

Each year, CDC sends suggested templates to the central health agencies for compilation of abortion data in aggregate. Aggregate abortion numbers, but no individual-level records, are requested for the following variables:

• Age in years of the woman (<15, 15--19 by individual year, 20--24, 25--29, 30--34, 35--39, ≥40);
• Gestational age in weeks at the time of abortion (≤6, 7--20 by individual week, ≥21);
• Race (black, white, Asian, Native Hawaiian/Pacific Islander, or American Indian/Alaska Native);
• Ethnicity (Hispanic or non-Hispanic);
• Method type (curettage,§ intrauterine instillation, medical [nonsurgical] abortion, or other¶);
• Marital status (married, including currently married or separated; unmarried, including never married, widowed, or divorced);
• Number of previous live births (0, 1, 2, 3, or ≥4);
• Number of previous abortions (0, 1, 2, or ≥3); and
• Maternal residence (the state, reporting area, or foreign country in which the woman obtaining the abortion lived; if additional details are unavailable, in-reporting area or out-of-reporting area).

In addition to sending templates for compiling information on race and ethnicity as separate variables, CDC has provided alternative templates since 2001 for the tabulation of aggregate cross-classified race/ethnicity data. Because few reporting areas returned these alternative templates in the past, 2008 is only the second year for which CDC has had sufficient data to report results by these cross-classified race/ethnicity categories (non-Hispanic white, non-Hispanic black, non-Hispanic other, and Hispanic).

Finally, both the original and alternative templates that CDC provides request that aggregate numbers for certain individual variables be cross-tabulated by a second variable. These cross-tabulations include gestational age (by age, method type, race, ethnicity, and race/ethnicity) and age and marital status (by race, ethnicity, and race/ethnicity).

In this report, medical abortions and abortions performed by curettage are further categorized by gestational age. For medical abortion, early medical abortion is defined as the administration of medication or medications (typically mifepristone followed by misoprostol) to induce an abortion at ≤8 weeks' gestation**; medical abortion at >8 weeks' gestation is defined as the administration of medication or medications (typically vaginal prostaglandins) to induce an abortion at >8 weeks' gestation. For curettage, abortions are categorized as having been performed at ≤13 weeks' gestation or at >13 weeks' gestation because of differences in technique used before and after 13 weeks (19). Finally, because intrauterine instillations cannot be performed early in gestation, abortions reported to have been performed by intrauterine installation at ≤12 weeks' gestation are excluded from calculation of the percentage of abortions by known method type.††

Measures of Abortion

Four measures of abortion are presented in this report: 1) the total number of abortions in a given population, 2) the percentage of abortions obtained within a given subpopulation, 3) the abortion rate (number of abortions per 1,000 women aged 15--44 years or other specific group within a given population), and 4) the abortion ratio (number of abortions per 1,000 live births within a given population). Although total numbers and percentages are useful measures for determining how many women have obtained an abortion, abortion rates adjust for differences in subpopulation size and reflect how likely abortion is among women in particular groups. Abortion ratios reflect the relative number of pregnancies in a population that end in abortion compared with live birth; abortion ratios change both according to the proportion of pregnancies in a population that are unintended and the proportion of unintended pregnancies that are ended. Abortion ratios also are influenced by the proportion of intended pregnancies that end in abortion; however, according to the most recent estimates, intended pregnancies account for a very small percentage of abortions (<5%) (22).

U.S. Census Bureau estimates of the resident female population of the United States, compiled by CDC (23--32), were used as the denominator for calculating abortion rates. Overall abortion rates were calculated from the population of women aged 15--44 years. For adolescents aged <15 years, abortion rates were based on the number of adolescents aged 13--14 years; similarly, for women aged ≥40 years, abortion rates were based on the number of women aged 40--44 years. For the calculation of abortion ratios, live birth data were obtained from CDC natality files (33).

Data Presentation and Analysis

This report provides state-specific and overall abortion numbers, rates, and ratios for the 49 areas that reported to CDC for 2008 (excludes California, Maryland, and New Hampshire). In addition, this report describes the characteristics of women who obtained abortions in 2008. However, because the completeness of reporting on the characteristics of women varies by year and by variable, this report only describes the characteristics of women from areas that met reporting standards (i.e., reported at least 20 abortions, provided data categorized in accordance with surveillance variables, and had <15% unknown values for a given characteristic). Cell values from 1 to 4 have been suppressed to maintain confidentiality. In addition, abortion rates and ratios were not calculated for groups with <20 abortions because results are considered unstable.

Most of the data in this report are presented by the reporting area in which the abortions were performed. In addition, 48 reporting areas§§ provided the number of abortions by the reporting area in which women lived. However, two of these reporting areas (Illinois and Wisconsin) reported characteristics for in-state residents but not for out-of-state residents. Four other reporting areas (Arizona, Iowa, Louisiana, and Massachusetts) provided only the total number of abortions for out-of-state residents without specifying individual states or areas of residence. As a result, abortion statistics in this report by area of residence are minimum estimates. In particular, they might be disproportionately low for reporting areas from which many women travel to other states to obtain abortion services, if they go to states with incomplete residence reporting.

For the purpose of evaluating trends in the overall number, rate, and ratio of reported abortions in the United States, data are presented for every year during 1999--2008. Linear regression analysis was used to assess the overall rate of change during 1999--2008 and during the first and second half of the period of analysis (1999--2003 and 2004--2008). In addition, the percentage change from the first to the last year was calculated for these three periods and from 2007 to 2008. Only the 45 reporting areas that provided data every year during 1999--2008 were included in these analyses. Similarly, for the analysis of certain additional variables (abortions by maternal age, gestational age, race, and ethnicity), annual data are presented for areas that met reporting standards every year during 1999--2008, and the percentage change was calculated for the same time periods (1999--2008, 1999--2003, 2004--2008, and 2007--2008). However, for other variables (marital status, number of previous abortions, and number of previous live births), annual data are not presented, and areas were included as long as they provided data that meet reporting standards for the years needed for percentage change calculations. To evaluate trends in the use of different methods for performing an abortion, reporting areas were included only if they met reporting standards and if they specifically included medical abortion as a method on their reporting form. Because approval of mifepristone for medical abortion was granted by the Food and Drug Administration (FDA) in September 2000 (34), 2001 was the first complete year during which early medical abortion was available in the United States. Thus, comparisons have been made between 2001 and 2008 and between 2007 and 2008.

Because some of the 49 areas that reported in 2008 were not included in certain trend analyses, summary measures for comparisons over time might differ slightly from the point estimates presented for all areas that reported in 2008.

Abortion Mortality

CDC has reported data on abortion-related deaths periodically since information on abortion mortality first was included in the 1972 abortion surveillance report (14). An abortion-related death is defined as a death resulting from a direct complication of an abortion (legal or illegal), an indirect complication caused by a chain of events initiated by an abortion, or an aggravation of a preexisting condition by the physiologic or psychologic effects of abortion (35) or as a pregnancy-related death in which the pregnancy outcome was induced abortion, regardless of the causal relation between the abortion and the death. An abortion is defined as legal if it is performed by a licensed clinician; an abortion is defined as illegal if it is performed by any other person. All deaths determined to be related causally to induced abortion have been classified as abortion related regardless of the time between the abortion and death.

Since 1987, CDC has monitored abortion-related deaths through its Pregnancy Mortality Surveillance System (36). Sources of data for abortion-related deaths have included state vital records, public health agencies, maternal mortality review committees, health-care providers and provider organizations, private citizens and citizen groups, and media reports, including computerized searches of full-text newspaper and other print media databases. For each death that possibly is related to abortion, CDC requests clinical records and autopsy reports. Two clinical epidemiologists review these reports to determine the cause of death and whether the death was abortion related. Each death is categorized by abortion type as legal induced, illegal induced, spontaneous, or unknown type. This report provides data on induced abortion-related deaths that occurred during 1972--2007; data for 2007 have not been published previously and are the most recent data available. Possible abortion-related deaths that occurred during 2008--2011 are under investigation. Although national case-fatality rates (the number of abortion-related deaths per 100,000 reported legal induced abortions) have been published for 1972--1997, this measure could not be calculated with CDC data for 1998--2007; because a substantial number of abortions have been documented in states that did not report to CDC during 1998--2007 (3,12), the total number of abortions was not available as the rate denominator.

Results

U.S. Totals

Among the 49 reporting areas that provided data for 2008,¶¶ a total of 825,564 abortions were reported. Of these abortions, 808,528 (97.9% of the total) were from the 45 reporting areas that provided data every year during 1999--2008.*** These same 45 areas reported 3,451,951 births for 2008, had an abortion rate of 16.0 abortions per 1,000 women aged 15--44 years, and had an abortion ratio of 234 abortions per 1,000 live births (Table 1). Compared with the previous year (2007), the total number of abortions decreased 0.3%, the abortion rate was unchanged, and the abortion ratio increased 1%. During 1999--2008, the total number, rate, and ratio of reported abortions decreased 3%, 4%, and 10%, respectively. However, regression analysis indicated that most of the decrease in the total number and rate of reported abortions occurred during the first half of the period of analysis. On average during 1999--2003, the number of reported abortions decreased by 3,956 abortions per year, and the abortion rate decreased by 0.1 abortions per 1,000 women per year. In contrast, during 2004--2008, average annual changes were slight. The number of reported abortions decreased by 1,004 abortions per year, and the abortion rate actually increased by 0.02 abortions per 1,000 women per year. The change in abortion ratios was more consistent. On average, abortion ratios decreased by 2.7 and 2.5 abortions per 1,000 live births per year, respectively, during 1999--2003 and 2004--2008 (Figure 1).

Occurrence and Residence

Total abortion numbers, rates, and ratios have been calculated by individual reporting area of occurrence and the residence of the women who obtained the abortions (Table 2). By reporting area of occurrence, a considerable range existed in the total number of reported abortions, ranging from four or fewer (Wyoming) to 89,469 (New York City); in the abortion rate, ranging from 4.6 (Mississippi) to 47.6 (New York City) abortions per 1,000 women†††; and in the abortion ratio, ranging from 59 (Idaho) to 732 (New York City) abortions per 1,000 live births.§§§ Similarly, a considerable range existed by residence¶¶¶ in the total number of reported abortions, ranging from 769 (Wyoming) to 82,670 (New York City); in the abortion rate, ranging from 6.2 (Utah) to 44.0 (New York City) abortions per 1,000 women; and in the abortion ratio, ranging from 66 (Utah) to 676 (New York City) abortions per 1,000 live births. Because of the substantial variation that also occurred among reporting areas in the percentage of abortions obtained by out-of-state residents, ranging from none (Wyoming) to 54.3% (District of Columbia), abortion rates and ratios calculated by maternal residence might provide a more accurate reflection of population trends. However, these measures must be viewed with caution because of the variation across reporting areas in methods used to record maternal residence and the resulting 11.5% of abortions reported without a state, territory, reporting area, or country of maternal residence.

Age

Among the 47 areas that reported by maternal age for 2008, women aged 20--29 years accounted for the majority (57.1%) of abortions and had the highest abortion rates (29.6 and 21.6 abortions per 1,000 women aged 20--24 and 25--29 years, respectively) (Figure 2, Table 3). Women in the youngest and oldest age groups (aged <15 or ≥40 years) accounted for the smallest percentage of abortions (0.5% and 3.1%, respectively) and had the lowest abortion rates (1.2 and 2.7 abortions per 1,000 women aged <15 and ≥40 years, respectively). Among the 43 reporting areas that provided data every year during 1999--2008, this pattern across age groups was stable, with the majority of abortions and the highest abortion rates occurring among women in their 20s and the lowest percentages of abortions and abortion rates occurring among women in the youngest and oldest age groups (Table 4). However, during 1999--2008, the abortion rate and percentage of abortions accounted for by women in the youngest age groups decreased, whereas the abortion rate and percentage of abortions accounted for by older women increased. Both during 1999--2003 and 2004--2008, abortion rates increased among adolescents aged ≤19 years and decreased among women aged ≥30 years. However, among women aged 20--24 years, abortion rates decreased during 1999--2003 and then leveled off during 2004--2008.

In contrast to the percentage distribution of abortion numbers and abortion rates, abortion ratios in 2008 were highest among adolescents aged ≤19 years and lowest among women aged 30--39 years (Figure 2, Table 3). Among the 43 reporting areas that provided data for every year during 1999--2008, abortion ratios decreased among all women aged ≥15 years. For most women aged ≥20 years (all groups except women aged 35--39 years), abortion ratios decreased both during 1999--2003 and during 2004--2008. However, for women aged 20--34 years, this trend was reversed from 2007 to 2008 when abortion ratios increased (Table 4).

Adolescents

Among the 45 areas that reported age by individual year among adolescents for 2008, adolescents aged ≤19 years accounted for 112,614 abortions (Table 5). The adolescent abortion rate was 10.7 abortions per 1,000 adolescents aged ≤19 years. Adolescents aged 18--19 years accounted for the majority (63.3%) of adolescent abortions and had the highest adolescent abortion rates (20.5 and 25.9 abortions per 1,000 adolescents aged 18 and 19 years, respectively); adolescents aged <15 years accounted for the smallest percentage of adolescent abortions (3.0%) and had the lowest adolescent abortion rate (1.2 abortions per 1,000 adolescents). Among the 40 reporting areas that provided data every year during 1999--2008, this pattern across age groups was stable, with older adolescents accounting for the largest percentage of adolescent abortions and having the highest abortion rates (Table 6). However, during 1999--2008, the distribution of adolescent abortions shifted toward older adolescents, whereas abortion rates decreased among adolescents of all ages. Greater decreases in abortion rates occurred during 1999--2003 than during 2004--2008; however, decreases continued from 2007 to 2008 for all adolescents aged ≥15 years.

The adolescent abortion ratio for 2008 was 345 abortions per 1,000 live births. Adolescent abortion ratios decreased with increasing age and were lowest among adolescents aged 19 years (Table 5). Among the 40 reporting areas that provided data for every year during 1999--2008, the difference in abortion ratios between younger and older adolescents increased, with a comparatively large increase among adolescents aged <15 years and a comparatively large decrease among adolescents aged 18--19 years (Table 6). The increase in abortion ratios among younger adolescents took place primarily during 1999--2003, whereas the decrease in abortion ratios among older adolescents took place primarily during 2004--2008.

Gestational Age

Among the 40 areas that reported gestational age at the time of abortion for 2008 (Table 7), the majority (62.8%) of abortions were performed at ≤8 weeks' gestation, and 91.4% were performed at ≤13 weeks' gestation. A total of 7.3% of abortions were performed at 14--20 weeks' gestation, and 1.3% were performed at ≥21 weeks' gestation. Among the 32 reporting areas that provided data on gestational age every year during 1999--2008 (Table 8), the percentage of abortions performed at ≤13 weeks' gestation was stable but shifted toward earlier gestational ages: abortions performed at ≤8 weeks' gestation increased 12%, whereas abortions performed at 9--13 weeks' gestation decreased 18%. The percentage increase in abortions performed at ≤8 weeks' was greatest during 1999--2003 but continued during 2004--2008; similarly, the percentage decrease in abortions performed at 9--13 weeks' was greatest during 1999--2003 but continued during 2004--2008. Throughout the period of analysis, the percentage of abortions performed at >13 weeks' gestation remained low (<10%). Abortions performed at ≥16 weeks' gestation decreased 13%--17% during 1999--2008, although this decrease only took place during 1999--2003 and did not continue during 2004--2008.

Among the 40 areas that reported the exact week of gestational age for abortions performed at ≤13 weeks' gestation in 2008, 33.6% were performed at ≤6 weeks' gestation, and 35.1% were performed at 7--8 weeks' gestation (Table 9). Among the remaining abortions at ≤13 weeks' gestation, the percentage contribution was progressively lower for each additional week of gestation: 10.5% of abortions at ≤13 weeks were performed at 9 weeks' gestation, whereas 3.2% were performed at 13 weeks' gestation. Among the 33 areas that reported by the exact week of gestational age for every year during 1999--2008, the percentage of abortions shifted over time toward earlier gestational ages: the percentage of abortions performed at ≤6 weeks' gestation increased 53%, whereas the percentage performed at 8--13 weeks' gestation decreased (Table 10); the percentage increase in abortions performed at ≤6 weeks' was greatest during 1999--2003 but continued during 2004--2008.

Method Type

Among the 40 areas that reported by method type for 2008 and included medical abortion on their reporting form for medical providers, 75.9% of abortions were performed by curettage at ≤13 weeks' gestation;14.6% were performed by early medical (nonsurgical) abortion, 8.5% were performed by curettage at >13 weeks' gestation, and all other methods were uncommon (Table 11). Among the 28 reporting areas that included medical abortion on their reporting form and provided this data for all 3 years of comparison (2001, the first full year following FDA approval of mifepristone for use in early medical abortion, as well as 2007 and 2008),**** the use of early medical abortion increased 17% from 2007 to 2008 and approximately 300% from 2001 to 2008 (from 3.4% of abortions in 2001 to 11.9% in 2007 and 13.9% in 2008). In contrast, use of curettage at ≤13 weeks' gestation decreased 3% from 2007 to 2008 and 12% from 2001 to 2008 (from 87.3% of abortions in 2001 to 79.0% in 2007 and 76.7% in 2008). Use of curettage at >13 weeks' gestation remained essentially unchanged (accounting for 8.6% of abortions in 2001, 8.3% in 2007, and 8.6% in 2008). All other methods consistently accounted for a small percentage of abortions (0.05%--0.7%).

Race

Among the 35 areas that reported race for 2008, white women (including Hispanic and non-Hispanic white women) accounted for the largest percentage (52.4%) of abortions; black women accounted for 40.2%, and women in the other races category accounted for 7.3% (Table 12). In contrast, black women had higher abortion rates and ratios than white women and women in the other races category (Table 12). Among the 26 reporting areas that provided data every year during 1999--2008, the percentage distribution of abortions by race changed little; although the percentage of abortions among women in the other races category increased, the percentage remained low (Table 13). Abortion rates decreased among women of all races during 1999--2008. However, among white women, decreases in abortion rates were greater during 1999--2003 than during 2004--2008. Among black women, decreases during 1999--2003 did not continue during 2004--2008, and from 2007 to 2008, abortion rates increased. Abortion ratios decreased during 1999--2008 among women of all races, and these decreases occurred both during 1999--2003 and during 2004--2008. However, this trend reversed among black women from 2007 to 2008 when their abortion ratio increased (Table 13).

Race/Ethnicity

Among the 28 areas that reported cross-classified race/ethnicity data for 2008 (Table 14), non-Hispanic white women and non-Hispanic black women accounted for 37.2% and 35.5% of all abortions. Hispanic women accounted for 21.1% of all abortions, and non-Hispanic women in the other races category accounted for 6.3%. Non-Hispanic white women had the lowest abortion rates (8.7 abortions per 1,000 women aged 15--44 years) and ratios (140 abortions per 1,000 live births), whereas non-Hispanic black women had the highest abortion rates (33.5 abortions per 1,000 women aged 15--44 years) and ratios (472 abortions per 1,000 live births). Among the 24 areas†††† that reported by race/ethnicity both in 2007 and 2008, increases in abortion rates and ratios were somewhat greater for non-Hispanic black women than for non-Hispanic white women and Hispanic women. Abortion rates increased 10% for non-Hispanic black women (from 32.2 abortions per 1,000 women in 2007 to 35.4 in 2008), 5% for non-Hispanic white women (from 8.6 abortions per 1,000 women in 2007 to 9.0 in 2008), and 2% for Hispanic women (from 20.0 abortions per 1,000 women in 2007 to 20.4 in 2008). Similarly abortion ratios increased 4% among non-Hispanic black women (from 481 abortions per 1,000 live births in 2007 to 501 in 2008), whereas they were more stable for non-Hispanic white women (at 145 abortions per 1,000 live births in 2007 and 144 in 2008) and for Hispanic women (at 201 abortions per 1,000 live births in 2007 to 196 in 2008). Because 2007 was the first year for which cross-classified race/ethnicity data were compiled, longer term trends could not be evaluated.

Ethnicity

Among the 32 areas that reported ethnicity for 2008, Hispanic women accounted for 19.5% of all abortions, with an abortion rate of 20.3 abortions per 1,000 women and an abortion ratio of 192 abortions per 1,000 live births (Table 15). These results are similar, albeit slightly lower, to those for Hispanic women who obtained abortions in the 27 reporting areas that provided cross-classified race/ethnicity data (Table 14). Among the 19 reporting areas that provided ethnicity data every year during 1999--2008, the percentage of abortions accounted for by Hispanic women increased 15% (Table 16). Abortion rates and ratios decreased among Hispanic women during 1999--2008. However, these decreases were greater during 1999--2003 than during 2004--2008 and did not continue from 2007 to 2008 (Table 16).

Marital Status

Among the 40 areas that reported marital status for 2008, 15.7% of all women were married, and 84.3% were unmarried (Table 17). For the 30 reporting areas§§§§ that provided these data for the relevant years of comparison, the percentage of abortions accounted for by unmarried women increased 4% during 1999--2008 (from 81.2% in 1999 to 84.4% in 2008); an increase occurred both during 1999--2003 and during 2004--2008.

Previous Live Births and Abortions

Among the 41 areas that reported by the number of previous live births for 2008, 40.6%, 46.1%, and 13.3% of all women who obtained abortions had previously had zero, one to two, or three or more live births, respectively (Table 18). Among the 35 reporting areas¶¶¶¶ that provided these data for the relevant years of comparison, the percentage of women who had no previous live births was stable during 1999--2008 (at 40.6% in 1999 and 40.7% in 2008). In contrast, during 1999--2008, the percentage of women who had one to two previous live births decreased 3% (from 47.6% in 1999 to 46.0% in 2008), and the percentage who previously had three or more live births increased 13% (from 11.8% in 1999 to 13.3% in 2008); for both groups the direction of change (increase or decrease) was consistent during 1999--2003 and 2004--2008.

Among the 42 areas that reported the number of previous abortions for 2008, the majority of women (55.6%) had not previously had an abortion; 36.4% and 8.0%, respectively, had previously had either one to two abortions, or three or more abortions (Table 19). Among the 33 reporting areas***** that provided data for the relevant years of comparison, the percentage of women who had not previously had an abortion increased 2% (from 54.1% in 1999 to 55.1% in 2008). The percentage of women who had one to two previous abortions decreased 4% (from 38.1% in 1999 to 36.5% in 2008), whereas the percentage of women who had obtained three or more previous abortions increased 8% (from 7.8% in 1999 to 8.4% in 2008). For women who had obtained zero or one to two previous abortions, the direction of change (increase or decrease) was consistent during 1999--2003 and 2004--2008; however, for women who had previously obtained three or more abortions, the increase occurred exclusively during 2004--2008.

Age and Marital Status by Race and Race/Ethnicity

In some reporting areas, women of each racial and racial/ethnic group were classified by age and marital status (Tables 20 and 21). By age, a consistent pattern existed across all racial and racial/ethnic groups, with the smallest percentage of abortions occurring among adolescents aged <15 years (0.3%--0.7%) and the largest percentage occurring among women aged 20--24 years (26.1%--33.6%). By marital status, a consistent pattern also existed across all racial and racial/ethnic groups, with a higher percentage of abortions occurring among women who were unmarried (65.3%--90.2%) than among those who were married (9.8%--34.7%).

Weeks of Gestation by Age, Race, Race/Ethnicity, and Method Type

In some reporting areas, women who obtained abortions at different gestational ages were categorized by age, race, and race/ethnicity (Tables 22 and 23). In every subgroup for these three variables, the largest percentage of abortions was obtained by ≤8 weeks' gestation. However, whereas 44.0% of adolescents aged <15 years and 53.2% of adolescents aged 15--19 years obtained an abortion by ≤8 weeks' gestation, 61.2%--70.0% of women aged ≥20 years obtained an abortion by this point in gestation (Figure 3; Table 22). Conversely, 19.0% of adolescents aged <15 years and 12.3% of adolescents 15--19 years obtained an abortion after 13 weeks' gestation, whereas this percentage ranged from 6.8%--8.9% for adult women. By race/ethnicity, 58.9% of non-Hispanic black women obtained an abortion at ≤8 weeks' gestation, whereas 66.9%--70.5% of women from other racial/ethnic groups obtained an abortion by this point in gestation. Non-Hispanic black women also obtained the highest percentage of abortions after 13 weeks' gestation; however, differences across racial/ethnic groups were less apparent than differences across age groups (Table 22).

Among women obtaining abortions in reporting areas that further categorized method type by gestational age, curettage accounted for the largest percentage of abortions within every gestational age category (Table 24). At ≤8 weeks' gestation, curettage accounted for a smaller percentage of abortions (76.9%) than at any other stage of gestation, and early medical abortion accounted for a comparatively high percentage of abortions (22.5%). At 9--20 weeks' gestation, curettage accounted for 96.0%--98.4% of all abortions and then decreased to 90.6% of abortions at ≥21 weeks' gestation. After 8 weeks' gestation, medical abortion accounted for 0.6%--1.7% of abortions until 18 weeks' gestation, when its use increased to 2.2% at 18--20 weeks and 7.7% at ≥21 weeks' gestation. Throughout gestation, intrauterine instillations and other methods accounted for a small percentage (0%--1.7%) of abortions.

Abortion Mortality

Using national data from the Pregnancy Mortality Surveillance System (36), CDC identified nine deaths for 2007 that were potentially related to abortion. These deaths were identified either by some indication of abortion on the death certificate, by reports from a health-care provider or public health agency, or from a media report. Investigation of these cases indicated that six of the nine deaths were related to legal abortion and none to illegal abortion (Table 25). One of the six deaths related to a legal induced abortion occurred after a medical (nonsurgical) abortion; this case has been described previously (37). Of the three deaths that were determined not to be related to a legal induced abortion, two were determined to be causally unrelated to the pregnancy or the abortion, and one was associated with a pregnancy outcome other than induced abortion. Possible abortion-related deaths that occurred during 2008--2011 are under investigation.

Discussion

For 2008, a total of 825,564 abortions were reported in the United States. Of these abortions, 808,528 (97.9% of the total) were from the 45 reporting areas that submitted data every year during 1999--2008, thus providing the information necessary for evaluating trends. These 45 areas reported 3,451,951 births for 2008, and had an abortion rate of 16.0 abortions per 1,000 women aged 15--44 years and an abortion ratio of 234 abortions per 1,000 live births. This represents essentially no change from 2007 in the total number (810,582) and rate (16.0 abortions per 1,000 women aged 15--44 years) of reported abortions and is consistent with the leveling off from decreases observed in the past. Indeed, previously reported average annual decreases in the total number and rate of abortions during 1996-2000 (13) were five times the average annual decreases for the same 45 reporting areas during 1999--2003; the rate of decrease leveled off even more during 2004--2008, when essentially no decrease occurred. Moreover, the last 1-year increase (from 2005 to 2006) in the total number and rate of reported abortions was accompanied by an equivalent increase in the total number of births in the United States and the fertility rate (live births per 1,000 women aged 15--44 years) (13,38); in contrast, the leveling off of abortion numbers and rates from 2007 to 2008 was accompanied by a decrease in births and fertility (39). This leveling off of abortion numbers in conjunction with a decrease in number of births is reflected by the increase in the abortion ratio from 2007 to 2008, which previously had been decreasing steadily.

In addition to overall population changes, this report highlights important age differences in abortion trends. Throughout the period covered by this report, women aged 20--29 years obtained the majority of abortions (55%--57%) and therefore accounted for most of the overall changes in abortion rates. In particular, women aged 20--24 years consistently accounted for approximately one third of all abortions, and although the abortion rates in this age group decreased during 1999--2003, they increased during 2004--2008. Hence women in this age group largely account for the recent leveling off of the decrease in abortion rates for the overall population.

In contrast to the abortion patterns among women aged 20--29 years, trends in abortion rates during 1999--2008 were more consistent for older women (for whom there was a steady increase) and adolescents (for whom there was a steady decrease). Because women aged ≥35 years consistently accounted for a small percentage of abortions (<11% during 1999--2008), they had a much smaller impact on overall abortion trends. Nonetheless, the persistent increase in abortion rates among women in this age group suggests that unintended pregnancy is a problem that women face throughout their reproductive years and that women in older age groups are increasingly affected.

The trends on adolescent abortions described in this report are important for monitoring progress toward reducing adolescent pregnancies in the United States. During 1991--2009, the adolescent birth rate in the United States decreased by 37% to its lowest level in the nearly 70 years these data have been collected (40,41). Although reporting of abortions lags behind reporting of births, data through 2005 indicate that the adolescent abortion rate decreased even more than the adolescent birth rate (5). Therefore, the historic decrease in the adolescent birth rate through 2005 can be attributed to a decrease in the adolescent pregnancy rate rather than to a decrease in the proportion of adolescents who continued their pregnancies through live birth. However, the long-term decrease in the adolescent birth rate was interrupted by a 5% increase from 2005 to 2007 (42). Because the adolescent abortion rate did not change substantially during this period, decreasing only 1% (14), most of the increase in adolescent births can be attributed to an increase in adolescent pregnancies rather than to an increasing tendency for adolescents to continue their pregnancies. In 2008, a 2% decrease in the adolescent birth rate occurred, consistent with the previous downward trend (39). Because the abortion rate in 2008 for adolescents aged 15--19 years also decreased 2%, the decrease in births once again might be attributed to a decrease in pregnancies rather than a decrease in the tendency for adolescents to continue their pregnancies. Given that the adolescent birth rate decreased 6% from 2008 to 2009 (43), 2009 abortion data, when available, will be important for determining the extent to which this large decrease can be attributed to a decrease in adolescent pregnancies.

The findings in this report on race and ethnicity reflect differences in patterns of obtaining abortions that have been well-documented and observed for many years (2--11). Comparatively high abortion rates and ratios among black women can be attributed to higher unintended pregnancy rates and a higher percentage of unintended pregnancies ending in abortion (44,45). Although data from some recent reports suggest that differences in measures of abortion between black women and women of other races have narrowed (10,11), the increase in abortion rates and ratios observed for black women in the 2008 CDC data reverses the suggestion of a downward trend from previous years (14). High abortion rates among Hispanic compared with non-Hispanic white women have been attributed to high pregnancy rates among Hispanic women (44,45). However, abortion ratios in these two groups have been more comparable: Hispanic women have tended to have a slightly higher percentage of pregnancies that are unintended but are no more likely than non-Hispanic white women to terminate unintended pregnancies (44). Changes from 2007 to 2008 in abortion rates and ratios for Hispanic women were slight. However, longer term changes are difficult to interpret from this report because records before 2007 for non-Hispanic women combined women from white, black, and other racial populations.

The findings presented in this report indicate that more women are obtaining abortions earlier in gestation, when the risks for complications are lowest (46--49). Among the areas that reported data every year during 1999--2008, the percentage of abortions performed at ≤8 weeks' gestation increased 12%. Moreover, among the areas that reported abortions at ≤13 weeks' gestation by individual week, a clear shift in the distribution toward earlier weeks of gestation was observed: during 1999--2008 the percentage performed at ≤6 weeks' gestation increased 53%, whereas the percentage performed at ≥8 weeks' gestation decreased. However, these changes were greater during 1999--2003 than during 2004--2008, suggesting that the increase in the percentage of abortions performed during the earliest stages of gestation has slowed in recent years. Moreover, the overall percentage of abortions performed at ≤13 weeks' gestation has changed little, and no additional decreases in the small proportion of abortions performed at ≥16 weeks' gestation have occurred since 2004.

Because the risks for abortion complications are the lowest early in gestation, it is important to understand the factors that cause women to delay their requests for pregnancy termination (50--52). This report suggests these factors might be especially pronounced for adolescents and black women. In these groups of women, a smaller percentage of abortions was obtained at ≤8 weeks' gestation, and among adolescents, in particular, a greater percentage of abortions was obtained at >13 weeks' gestation. Because women with low incomes frequently need additional time to raise the necessary funds and make arrangements for an abortion (50,53), some delays among black women might be related to their higher poverty rates (54). Delays among adolescents might reflect the fact that they often take longer to suspect and then confirm they are pregnant (50,52) and might take longer to arrange an abortion because of parental involvement laws (55). In addition, some pregnant adolescents approaching age 18 years wait until they are old enough to obtain an abortion without parental involvement (56,57), thereby delaying the timing of their abortion.

The trend among women to obtain abortions earlier in pregnancy, although not observed equally among all subgroups of women, has been facilitated by changes in abortion practices. Curettage has remained the most common method for performing abortions. Although for many years this type of abortion was performed only after the initial weeks of gestation, the development of highly sensitive pregnancy tests and transvaginal ultrasonography increasingly have allowed clinicians to diagnose pregnancy and confirm its termination at ≤6 weeks' gestation (58--63). In addition, the use of medical abortion might have contributed to the increasing percentage of abortions performed early in gestation. In September 2000, FDA approved mifepristone for use in early medical abortion (34), and in 2005, the American College of Obstetricians and Gynecologists endorsed an evidence-based protocol that can be used up to 63 days of gestation (18). In 2008, 62.8% of abortions were performed at ≤8 weeks' gestation and thus were eligible for early medical abortion; 22.5% of these eligible abortions and 14.6% of all abortions were reported as early medical abortions. The use of early medical abortion has increased substantially since FDA approved the use of mifepristone: during 2001--2008, the percentage of all reported abortions accounted for by this method increased approximately 300%. Moreover, whereas the rate of increase leveled off after the initial years of approval (64), the proportional use of this method has continued to increase, with the percentage of all abortions reported as early medical abortion increasing 17% from 2007 to 2008.

The average annual number of deaths associated with known legal induced abortions during the latest decade (1998--2007) was 57% lower than during the first decade following legalization of abortion (1972--1981) and 22% lower than that during 1982--1997. In 2007, six women died from causes known to be associated with legal abortion, and none died as a result of known illegal abortions. CDC data cannot be used to calculate national case-fatality rates for 1998--2007 because some states (four during 1998--1999, three during 2000--2005 and 2007, and two during 2006), including California, did not report abortion surveillance data. Because a substantial number of abortions have been documented in California (3,12), CDC data cannot be used to approximate the total number of abortions as the rate denominator.

Limitations

The findings in this report are subject to at least four limitations. First, because reporting requirements are established by the individual reporting areas (16), the collection of data varies, and CDC is unable to obtain the total number of abortions performed in the United States. During 1999--2008, the total annual number of abortions recorded by CDC was 65%--69% of the number recorded by the Guttmacher Institute (12), which uses numerous active follow-up techniques to increase the completeness of the data obtained through its periodic national survey of abortion providers (12). Although most reporting areas collect and send abortion data to CDC, this information is given to CDC voluntarily. Consequently, during 1999--2008, seven of the 52 reporting areas did not provide CDC data on a consistent annual basis, and for 2008, CDC did not obtain any information from California, Maryland, or New Hampshire.††††† In addition, whereas most of the reporting areas that send abortion data to CDC have laws requiring medical providers to submit a report for every abortion they perform to a central health agency, in New Jersey and the District of Columbia, medical providers submit this information voluntarily (15). As a result, the abortion numbers these areas report to CDC tend to be incomplete.§§§§§ Moreover, even in states that legally require medical providers to submit a report for all the abortions they perform, enforcement of this requirement varies (66). Consequently, several other reporting areas provide CDC with incomplete numbers.¶¶¶¶¶

Second, because reporting requirements are established by the individual reporting areas, many states have developed reporting forms that do not resemble the template CDC created for technical guidance (17). Consequently, many reporting areas do not collect all the information CDC compiles on the characteristics of women obtaining abortions (e.g., age, race, and ethnicity) (66). Similarly, some reporting areas do not specifically include medical abortion as one of the potential methods for terminating a pregnancy (15). Although missing demographic information can reduce the extent to which the statistics in this report represent all women in the United States, four nationally representative surveys of women obtaining abortions in 1987, 1994--1995, 2001--2002, and 2008 (7--10) have produced distributions, for most characteristics, that are nearly identical to the distributions reported by CDC. The one exception is the distribution of abortions by race/ethnicity. In particular, the percentage of abortions accounted for by black women is higher in this report than the percentage in reports based on nationally representative survey results (10). In addition, the greater decrease in abortion rates for black women compared with women of other racial/ethnic groups based on nationally representative survey results (11) is not supported by the data in this report. These differences likely are attributable both to the comparatively high degree of measurement error for this variable that reduces the reliability of national survey results (10,11) and to the fact that the number of states that report to CDC by race/ethnicity continues to be somewhat lower than for other demographic variables. Importantly, some of the reporting areas that have not reported cross-classified race/ethnicity data to CDC (e.g., California, Florida, and Illinois) have large enough populations of minority women that the absence of data from these areas reduces the representativeness of CDC data. Similarly, for the measurement of medical abortion, CDC's early estimates might not as accurately represent the proportional contribution of this method because of the comparatively small number of reporting areas that provided this information. However, since 2001, the first full year after FDA approval of mifepristone for early medical abortion, more reporting areas have begun to specifically request information from abortion providers on the use of this method. As more states add medical abortion to their reporting forms, CDC estimates of the proportional contribution of this method should improve; however, trend analyses will continue to be affected by the incompleteness of early data.

Third, abortion data are compiled and reported to CDC by the central health agency of the reporting area in which the abortion was performed rather than the reporting area in which the woman lived. This inflates abortion statistics for reporting areas in which a high percentage of abortions are obtained by out-of-state residents and undercounts abortions for states with limited abortion services, more stringent legal requirements for obtaining an abortion, or geographic proximity to services in another state. To adjust for these biases, CDC attempts to categorize abortions by residence in addition to occurrence. However, CDC was unable to identify the reporting area, territory, or country of residence for 11.5% of reported abortions.

Finally, adjustments for socioeconomic status cannot be made without data on education or income, and joint analysis of many variables of interest (e.g., age, race, and ethnicity) is precluded because reporting areas provide CDC with aggregate numbers rather than individual-level records.

Public Health Implications

Ongoing abortion surveillance is important for several reasons. First, abortion surveillance is needed to guide and evaluate programs aimed at preventing unintended pregnancies. Because pregnancy intentions are complex and difficult to assess (67--75), abortion provides an important measure of pregnancies that are unwanted. Second, routine abortion surveillance is needed to assess changes in clinical practice patterns over time. Information in this report on the prevalence of abortions performed through different methods (e.g., medical or curettage) and at different gestational ages provides the denominator data that are necessary for analyses of the relative safety of abortion practices. Finally, statistics on the number of pregnancies ending in abortion are needed in conjunction with data on births and fetal losses to more accurately estimate the number of pregnancies in the United States and determine rates for various outcomes (e.g., adolescent pregnancy rates) (76).

According to the most recent national estimates, nearly one fifth of all pregnancies in the United States end in abortion (5). Multiple social, cultural, economic, and political factors are known to influence the incidence of abortion: the availability of abortion providers (12,77--79); the adoption of state regulations, such as mandatory waiting periods and parental involvement laws (55,80); increasing acceptance of nonmarital childbearing (81,82); shifts in the racial/ethnic composition of the U.S. population (83,84); and changes in the economy and the resulting impact on fertility preferences and access to health-care services, including contraception (85,86). However, in spite of these multiple influences, efforts to reduce the incidence of abortion need to focus on preventing unintended pregnancy. Indeed, nearly all abortions are preceded by an unintended pregnancy, with most recent estimates suggesting that intended pregnancies account for <5% of all abortions (22), including those which presumably are performed for maternal medical indications and fetal abnormalities. Providing women with the knowledge and resources necessary to make decisions about their sexual behavior and use of contraception can help them avoid unintended pregnancies. However, efforts to reduce unintended pregnancy in the United States have been challenging. Findings from the National Survey of Family Growth (NSFG), the primary national source of data on unintended pregnancy in the United States, suggest that unintended pregnancy decreased during 1982--1995 in conjunction with an increase in contraceptive use among women at risk for unintended pregnancy****** (87--89). However, data from the 2002 and 2006--2008 NSFGs suggest that no additional improvements have occurred: contraceptive use among women at risk for unintended pregnancy has decreased; only small gains have been made in the use of the most effective forms of reversible contraception, such as intrauterine devices and hormonal implants (90); and no additional progress has been made toward reducing unintended pregnancy (44,45). As part of the Patient Protection and Affordable Care Act, the U.S. Department Health and Human Services charged the Institute of Medicine with identifying which preventive services are important to women's health and should be covered at no cost to patients. Following the Institute of Medicine's recommendation (91), the full range of FDA-approved contraception methods, sterilization procedures, and patient education and counseling for women with reproductive capacity will be covered without cost sharing in new health plans beginning in August 2012. The removal of cost as one barrier to correct and consistent contraceptive use might contribute to a reduction in the number of unintended pregnancies and consequently the number of abortions that are performed in the United States.

Acknowledgments

This report is based, in part, on contributions by Sonya B. Gamble, Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC; Jessica Reno, Rollins School of Public Health, Emory University, Atlanta, Georgia; and Kristi Seed, Science Applications International Corporation, Atlanta, Georgia.

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