Abortion Surveillance — United States, 2010

Please note: An erratum has been published for this article. To view the erratum, please click here.

Karen Pazol, PhD

Andreea A. Creanga, MD, PhD

Kim D. Burley

Brenda Hayes, MPA

Denise J. Jamieson, MD

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: 2010.

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). The reporting areas provide this information voluntarily. For 2010, data were received from 49 reporting areas. For the purpose of trend analysis, abortion data were evaluated from the 46 areas that reported data every year during 2001–2010. Census and natality data, respectively, were used to calculate abortion rates (number of abortions per 1,000 women) and ratios (number of abortions per 1,000 live births).

Results: A total of 765,651 abortions were reported to CDC for 2010. Of these abortions, 753,065 (98.4%) were from the 46 reporting areas that provided data every year during 2001–2010. Among these same 46 reporting areas, the abortion rate for 2010 was 14.6 abortions per 1,000 women aged 15–44 years, and the abortion ratio was 228 abortions per 1,000 live births. Compared with 2009, the total number and rate of reported abortions for 2010 decreased 3% and reached the lowest levels for the entire period of analysis (2001–2010); the abortion ratio was stable, changing only 0.4%. From 2001 to 2010, the total number, rate, and ratio of reported abortions decreased 9%, 10%, and 8%, respectively. Given the 3% decrease from 2009 to 2010 in the total number and rate of reported abortions, in combination with the 5% decrease that had occurred in the previous year from 2008 to 2009, the overall decrease for both measures was greater during 2006–2010 than during 2001–2005, despite the annual variations that resulted in no net decrease during 2006–2008.

In 2010 and throughout the period of analysis, women in their 20s accounted for the majority of abortions and had the highest abortion rates, whereas women in their 30s and older accounted for a much smaller percentage of abortions and had lower abortion rates. In 2010, women aged 20–24 and 25–29 years accounted for 32.9% and 24.5% of all abortions, respectively, and had abortion rates of 26.7 and 20.2 abortions per 1,000 women aged 20–24 and 25-29 years, respectively. In contrast, women aged 30–34, 35–39, and ≥40 years accounted for 15.3%, 8.9%, and 3.4% of all abortions, respectively, and had abortion rates of 13.2, 7.6, and 2.8 abortions per 1,000 women aged 30–34 years, 35–39 years, ≥40 years, respectively. Throughout the period of analysis, abortion rates decreased among women aged 20–24 and 25–29 years, whereas they increased among women aged ≥40 years.

In 2010, adolescents aged 15–19 years accounted for 14.6% of all abortions and had an abortion rate of 11.7 abortions per 1,000 adolescents aged 15–19 years. Throughout the period of analysis, the percentage of all abortions accounted for by adolescents and the adolescent abortion rate decreased.

In contrast to the percentage distribution of abortions and abortion rates by age, abortion ratios in 2010 and throughout the entire period of analysis were highest among adolescents and lowest among women aged 30–39 years. Abortion ratios decreased from 2001 to 2010 for women in all age groups except for those aged <15 years, for whom they increased.

In 2010, most (65.9%) abortions were performed at ≤8 weeks' gestation, and 91.9% were performed at ≤13 weeks' gestation. Few abortions (6.9%) were performed at 14–20 weeks' gestation, and even fewer (1.2%) were performed at ≥21 weeks' gestation. From 2001 to 2010, the percentage of all abortions performed at ≤8 weeks' gestation increased 10%, whereas the percentage performed at >13 weeks' decreased 10%. Moreover, among abortions performed at ≤13 weeks' gestation, the distribution shifted toward earlier gestational ages, with the percentage of these abortions performed at ≤6 weeks' gestation increasing 36%.

In 2010, a total of 72.4% of abortions were performed by curettage at ≤13 weeks' gestation, 17.7% were performed by early medical abortion (a nonsurgical abortion at ≤8 weeks' gestation), and 8.3% were performed by curettage at >13 weeks' gestation. Among abortions that were performed at ≤8 weeks' gestation, and thus were eligible for early medical abortion on the basis of gestational age, 26.5% were completed by this method. From 2009 to 2010, the use of early medical abortion increased 13%.

Deaths of women associated with complications from abortions for 2010 are being investigated under CDC's Pregnancy Mortality Surveillance System. In 2009, the most recent year for which data were available, eight women were identified to have died as a result of complications from known legal induced abortions. No reported deaths were associated with illegal induced abortions.

Interpretation: Among the 46 areas that reported data every year during 2001–2010, the gradual decrease that had occurred during previous decades in the total number and rate of reported abortions continued through 2005, whereas year-to-year variation from 2006 to 2008 resulted in no net change during this later period. However, the large decreases that occurred both from 2008 to 2009 and from 2009 to 2010 resulted in a greater overall decrease during 2006–2010 as compared with 2001–2005 and the lowest number and rate of reported abortions for the entire period of analysis.

Public Health Actions: Unintended pregnancy is the major contributor to abortion. Because unintended pregnancies are rare among women who use the most effective methods of reversible contraception, increasing access to and use of these methods can help further reduce the number of abortions performed in the United States. The data in this report can help program planners and policy makers identify groups of women at greatest risk for unintended pregnancy and help guide and evaluate prevention efforts.

Introduction

This report is based on abortion data for 2010 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). Data were obtained every year during 2001-2010 from 46 reporting areas (excluding Alaska, California, Louisiana, Maryland, New Hampshire, and West Virginia) and were used for the purpose of trend analyses. 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 the 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 more recently, during 2006–2008, an interruption occurred in the previously sustained pattern of decrease (12–15). Continued surveillance is needed to monitor long-term changes in the incidence of abortion 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 all abortions to a central health agency (16). However, these central health agencies voluntarily report abortion data to CDC and provide only aggregate numbers for the abortion data they have collected through their independent surveillance systems (17). Nonetheless, although reporting to CDC is voluntary, most reporting areas provide their aggregate abortion numbers: during 2001–2010, a total of 46 reporting areas provided CDC a continuous annual record of abortion numbers,† and in 2010, CDC obtained aggregate abortion numbers from 49 reporting areas (excluding California, Maryland, and New Hampshire).

Although CDC obtains abortion numbers from most of the central health agencies, the level of detail that it 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 collaborated with the National Association of Public Health Statistics and Information Systems (NAPHSIS) to develop reporting standards and provide technical guidance for vital statistics personnel who collect and summarize abortion data within the United States. However, because the collection of abortion data is not federally mandated, many reporting areas have developed their own forms and do not 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, or ≥40)
• Gestational age in weeks at the time of abortion (≤6, 7–20 by individual week, or ≥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] or 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)
• Maternal residence (the state, reporting area, territory, or foreign country in which the woman obtaining the abortion lived, or, if additional details are unavailable, in-reporting area versus 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. Before 2007, few reporting areas returned these alternative templates. Therefore, 2010 is only the fourth 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 provided by CDC request that aggregate numbers for certain variables be cross-tabulated by a second variable. These cross-tabulations include gestational age (separately by age, by method type, by race, by ethnicity, and by race/ethnicity) and age and marital status (separately by race, by ethnicity, and by 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 by women in a given population, 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 population size and reflect how likely abortion is among women in particular groups. Abortion ratios measure the relative number of pregnancies in a population that end in abortion compared with live birth. Abortion ratios are influenced both by the proportion of pregnancies in a population that are unintended and the proportion of unintended pregnancies that end in abortion. Abortion ratios also are influenced by the proportion of intended pregnancies that end in abortion; however, 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, were used as the denominator for calculating abortion rates (23-32). Overall abortion rates were calculated from the population of women aged 15–44 years living in the areas that provided data. 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) and included births to women of all ages living in the reporting areas that provided abortion data.

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 2010 (excludes California, Maryland, and New Hampshire). In addition, this report describes the characteristics of women who obtained abortions in 2010. Because the completeness of reporting on the characteristics of women varies by year and by variable, this report only describes the characteristics of women obtaining abortions in 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). Cells with a value in the range of 1–4 have been suppressed to maintain confidentiality. In addition, abortion rates and ratios have been omitted for groups with <20 abortions because results are considered unstable.

Although most of the data in this report are presented by the reporting area in which the abortions were performed, 48 reporting areas§§ also provided the number of abortions by maternal residence. However, two of these reporting areas (Illinois and Wisconsin) reported certain characteristics for in-state residents but not for out-of-state residents. Three other reporting areas (Iowa, Louisiana, and Massachusetts) provided only the total number of abortions for out-of-state residents without specifying individual states or areas of residence from which these women came. As a result, abortion statistics in this report by area of residence are minimum estimates and might be disproportionately low for reporting areas from which many women travel to other states to obtain abortion services.

For the purpose of evaluating overall trends in the number, rate, and ratio of reported abortions, annual data are presented for the 46 areas that reported every year during 2001–2010. Linear regression analysis was used to assess the overall rate of change among these areas during 2001–2010 and during the first and second half of the period of analysis (2001–2005 and 2006–2010). Percentage change calculations (for 2009 to 2010 and for 2001 to 2010) also were calculated with the same 46 areas that provided data for every year included in this report.

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 2001–2010, and the percentage change was calculated for 2001 to 2010, 2001 to 2005, 2006 to 2010, and 2009 to 2010. For other variables (method for performing an abortion, 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 met 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 some of the 49 areas that reported for 2010 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 for 2010.

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 (34,35). 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 (36). All deaths determined to be related causally to induced abortion are classified as abortion-related regardless of the time between the abortion and death. In addition, any pregnancy-related death in which the pregnancy outcome was induced abortion regardless of the causal relation between the abortion and the death is considered an abortion-related 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.

Since 1987, CDC has monitored abortion-related deaths through its Pregnancy Mortality Surveillance System (37). 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 medical 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 in 2009, the most recent year for which data are available. Data on induced abortion-related deaths that occurred during 1972–2008 already have been published (35) and possible abortion-related deaths that occurred during 2010–2013 are under investigation. For 1998–2009, surveillance data reported to CDC cannot be used alone to calculate national case-fatality rates (number of legal induced abortion-related deaths per 100,000 reported legal induced abortions in the United States) because some states (four during 1998–1999, three during 2000–2005 and 2007–2009, and two during 2006), including California, did not report abortion surveillance data. Thus, national legal induced abortion case-fatality rates were calculated with denominator data from a more complete source on the total number of abortions performed in the United States (12). Because rates based on ≤20 deaths are highly variable (38), national legal induced abortion case-fatality rates were calculated for consecutive 5-year periods during 1973–2002 and a 7-year period during 2003–2009.

Results

U.S. Totals

Among the 49 reporting areas that provided data for 2010, a total of 765,651 abortions were reported. Of these abortions, 753,065 (98.4%) were obtained in the 46 reporting areas that provided data every year during 2001–2010.¶¶ These same 46 areas had an abortion rate of 14.6 abortions per 1,000 women aged 15–44 years and an abortion ratio of 228 abortions per 1,000 live births (Table 1). Compared with 2009, the total number of abortions reported for the same 46 areas decreased 3% (from 777,239). The abortion rate for these 46 areas also decreased 3% (from 15.0 abortions per 1,000 women aged 15–44 years), while the abortion ratio was stable (changing only 0.4% from 227 abortions per 1,000 live births). From 2001 to 2010, the total number of reported abortions decreased 9% (from 826,719), the abortion rate decreased 10% (from 16.2 abortions per 1,000 women aged 15–44 years), and the abortion ratio decreased 8% (from 249 abortions per 1,000 live births) (Figure 1). For the total number and rate, but not the ratio of reported abortions, the annual rate of decrease fitted from the regression analysis was greater during 2006–2010 than during 2001–2005. During 2006–2010, the number of reported abortions decreased by 19,924 abortions per year, the abortion rate decreased by 0.40 abortions per 1,000 women per year, and the abortion ratio decreased by 2.1 abortions per 1,000 live births per year. In contrast, during 2001–2005, the number of reported abortions decreased by only 5,405 abortions per year, and the abortion rate decreased by only 0.13 abortions per 1,000 women per year, while the abortion ratio decreased by 3.5 abortions per 1,000 live births per year.

Occurrence and Residence

Abortion numbers, rates, and ratios have been calculated by individual state or reporting area of occurrence and the residence of the women who obtained the abortions (Table 2). By occurrence, a considerable range existed*** in the abortion rate (ranging from 3.8 abortions per 1,000 women aged 15–44 years in Mississippi to 28.6 in New York [city and state combined]), and the abortion ratio (ranging from 57 abortions per 1,000 live births in Mississippi to 474 in New York [city and state combined]). Similarly, a considerable range existed by residence††† in the abortion rate (ranging from 5.2 abortions per 1,000 women aged 15–44 years in South Dakota to 27.6 in New York [city and state combined]), and the abortion ratio (ranging from 67 abortions per 1,000 live births in South Dakota to 458 in New York [city and state combined]). Because of the substantial variation that also occurred among reporting areas in the percentage of abortions obtained by out-of-state residents§§§ (ranging from 0.4% in Hawaii to 52.4% in the District of Columbia), abortion rates and ratios calculated by maternal residence might provide a more accurate reflection of the state-specific patterning of abortion. However, these measures must be viewed with caution because states vary in the level of detail they collect on maternal residence and as a result, 11.4% of abortions were reported to CDC without information on maternal residence.

Age

Among the 46 areas that reported by maternal age for 2010, women in their 20s accounted for the majority (57.4%) of abortions and had the highest abortion rates (26.7 and 20.2 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 3.4%, respectively) and had the lowest abortion rates (1.0 and 2.8 abortions per 1,000 women aged <15 and ≥40 years, respectively). Among the 43 reporting areas that provided data every year during 2001–2010, this pattern across age groups was stable, with the majority of abortions and the highest abortion rates occurring among women aged 20–29 years and the lowest percentages of abortions and abortion rates occurring among women in the youngest and oldest age groups (Table 4). However, from 2001 to 2010 the abortion rate and percentage of abortions accounted for by younger women decreased, whereas the abortion rate and percentage of abortions accounted for by older women increased. Among women aged <30 years, decreases in the abortion rate were greatest from 2006 to 2010, but also occurred from 2001 to 2005 and resulted in overall decreases ranging from 12% to 33%. In contrast, among women aged ≥40 years, abortion rates increased during both periods, resulting in an overall increase of 12%. Among women aged 30–39 years, abortion rates varied more from year to year, resulting in smaller overall changes.

In contrast to the percentage distribution of abortion numbers and abortion rates, abortion ratios in 2010 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 2001–2010, abortion ratios decreased among all women aged ≥15 years. For most age groups ≥15 years, abortion ratios decreased both from 2001 to 2005 and from 2006 to 2010. However for women aged 20–24 years, abortion ratios decreased from 2001 to 2005 but then increased from 2006 to 2010 (Table 4).

Adolescents

Among the 45 areas that reported age by individual year among adolescents for 2010, adolescents aged 18–19 years accounted for the majority (64.5%) of adolescent abortions and had the highest adolescent abortion rates (16.1 and 20.9 abortions per 1,000 adolescents aged 18 and 19 years, respectively); adolescents aged <15 years accounted for the smallest percentage of adolescent abortions (3.1%) and had the lowest adolescent abortion rate (1.0 abortions per 1,000 adolescents aged 13–14 years) (Table 5). Among the 41 reporting areas that provided data for adolescents by individual year of age every year during 2001–2010, this pattern across age groups was stable, with older adolescents consistently accounting for the largest percentage of adolescent abortions and having the highest abortion rates (Table 6). Although the percentage of abortions accounted for by adolescents aged 19 years increased from 2001 to 2010, abortion rates decreased among adolescents of all ages; these decreases occurred both from 2001 to 2005 and from 2006 to 2010, and continued for all adolescents ≥15 years from 2009 to 2010.

In 2010, adolescent abortion ratios decreased with increasing age and were lowest among adolescents aged 19 years (Table 5). Among the 41 reporting areas that provided data for adolescents by individual year of age for every year during 2001–2010, abortion ratios increased among adolescents aged ≤15 years and decreased among adolescents aged >15 years (Table 6).

Gestational Age

Among the 37 areas that reported gestational age at the time of abortion for 2010 (Table 7), the majority (65.9%) of abortions were performed at ≤8 weeks' gestation, and 91.9% were performed at ≤13 weeks' gestation. Few abortions (6.9%) were performed at 14–20 weeks' gestation, and even fewer (1.2%) were performed at ≥21 weeks' gestation. Among the 30 reporting areas that provided data on gestational age every year during 2001–2010 (Table 8), the percentage of abortions performed at ≤13 weeks' gestation increased only slightly. However, within this gestational age range, a shift occurred toward earlier gestational ages, with abortions performed at ≤8 weeks' gestation increasing 10% and abortions performed at 9-13 weeks decreasing 17%. The percentage increase in abortions performed at ≤8 weeks' was greatest from 2001 to 2005 but it continued from 2006 to 2010. During 2001–2010, the percentage of abortions performed at >13 weeks' gestation remained low (≤9.1%), and abortions performed at ≥16 weeks' gestation decreased 13%–19%.

Among the subset of abortions performed at ≤13 weeks' gestation in 2010, 37.8% were performed at ≤6 weeks' gestation (Table 9). Among the remaining abortions at ≤13 weeks' gestation, the percentage contribution was progressively lower for each additional week of gestation: 19.3% were performed at 7 weeks' gestation, whereas 2.9% were performed at 13 weeks' gestation. Among the 30 areas that reported by the exact week of gestational age for every year during 2001–2010, the percentage of abortions shifted over time toward earlier gestational ages: among abortions performed at ≤13 weeks' gestation, those that were performed at ≤6 weeks' gestation increased 36%, whereas the percentage performed at 7–13 weeks' gestation decreased up to 23% (Table 10); the percentage increase in abortions performed at ≤6 weeks' was greatest from 2001 to 2005, but this increase continued from 2006 to 2010.

Method Type

Among the 38 areas that reported by method type for 2010 and included medical abortion on their reporting form for medical providers, 72.4% of abortions were performed by curettage at ≤13 weeks' gestation, 17.7% were performed by early medical (nonsurgical) abortion, 8.3% were performed by curettage at >13 weeks' gestation, and all other methods were uncommon (Table 11). Among the 26 reporting areas that included medical abortion on their reporting form and provided this data for the relevant years of comparison (2001, 2005, 2006, 2009, and 2010),¶¶¶ the use of early medical abortion increased 13% from 2009 to 2010 (from 15.2% of abortions in 2009 to 17.2% in 2010); from 2001 to 2010, use of medical abortion increased approximately 400% (from 3.4% of abortions in 2001 to 17.2% in 2010). Large increases occurred both from 2001 to 2005 (approximately 200% from 3.4% of abortions in 2001 to 9.9% in 2005), and from 2006 to 2010 (approximately 65% from 10.5% of abortions in 2006 to 17.2% in 2011). In contrast, use of curettage at ≤13 weeks' gestation decreased 4% from 2009 to 2010 and 17% over the entire period of analysis (from 87.2% of abortions in 2001 to 75.5% in 2009 and 72.8% in 2010). Similar decreases in use of curettage at ≤13 weeks' gestation were observed from 2001 to 2005 and from 2006 to 2010. All other methods consistently accounted for a small percentage of abortions (0.05%–1.3%).

Race/Ethnicity

Among the 28 areas that reported cross-classified race/ethnicity data for 2010 (Table 12), non-Hispanic white women and non-Hispanic black women accounted for the largest percentages of abortions (36.8% and 35.7%, respectively), whereas Hispanic women and non-Hispanic women in the other races category accounted for smaller percentages (21.0% and 6.5%, respectively). Non-Hispanic white women had the lowest abortion rates (8.6 abortions per 1,000 women aged 15–44 years) and ratios (141 abortions per 1,000 live births), whereas non-Hispanic black women had the highest abortion rates (31.8 abortions per 1,000 women aged 15–44 years) and ratios (483 abortions per 1,000 live births).

Among the 22 areas**** that reported by race/ethnicity every year during 2007–2010, abortion rates decreased for all racial/ethnic groups, although decreases for non-Hispanic black women were smaller than for other groups. For non-Hispanic white women the abortion rate decreased 11% (from 9.3 abortions per 1,000 women in 2007 to 8.3 in 2010), for Hispanic women it decreased 9% (from 20.7 abortions per 1,000 women in 2007 to 18.9 in 2010), and for non-Hispanic black women it decreased 5% (from 34.8 abortions per 1,000 women in 2007 to 33.2 in 2010). In contrast, abortion ratios decreased among non-Hispanic white women but not among women in any other racial/ethnic group. For non-Hispanic white women, the abortion ratio decreased 6% (from 144 abortions per 1,000 live births in 2007 to 136 in 2010), whereas the abortion ratio increased 3% for non-Hispanic black women (from 486 abortions per 1,000 live births in 2007 to 503 in 2010) and 8% for Hispanic women (from 204 abortions per 1,000 live births in 2007 to 221 in 2010). Data also are reported separately by race and by ethnicity for 2010 (Tables 13 and 15) and for 2001–2010 (Tables 14 and 16).

Marital Status

Among the 38 areas that reported by marital status for 2010, 14.7% of all women who obtained abortions were married and 85.3% were unmarried (Table 17). The abortion ratio was 52 abortions per 1,000 live births for married women, and 438 abortions per 1,000 live births for unmarried women. For the 32 reporting areas†††† that provided these data for the relevant years of comparison (2001, 2005, 2006, 2009, and 2010), the percentage of abortions accounted for by unmarried women increased 4% from 2001 to 2010 (from 81.7% in 2001 to 85.3% in 2010); similar increases of approximately 2% occurred both from 2001 to 2005 and from 2006 to 2010. Among married women, the abortion ratio decreased 19% from 2001 to 2010 (from 64 to 52 abortions per 1,000 live births), with similar decreases of approximately 10% occurring from 2001 to 2005 and from 2006 to 2010. Among unmarried women, the abortion ratio decreased 21% from 2001 to 2010 (from 570 to 449 abortions per 1,000 live births). For unmarried women, the decrease was somewhat greater for 2001 to 2005 (13%) than for 2006 to 2010 (7%).

Previous Live Births and Abortions

Data from the 39 areas that reported the number of previous live births for women who obtained abortions in 2010 show that 40.3%, 45.9%, and 13.8% of these women had zero, one to two, or three or more previous live births, respectively (Table 18). Among the 30 reporting areas§§§§ that provided these data for the relevant years of comparison (2001, 2005, 2006, 2009, and 2010), the distribution of abortions by the number of previous live births was stable, although there was a slight increase among women who had zero or three or more previous live births, and a slight decrease among women who had one to two previous live births. Among the areas included in this comparison, 39.3%, 48.2%, and 12.5% of women had zero, one to two, or three or more previous live births, respectively in 2001; by contrast 41.0%, 45.8% and 13.2% of women had zero, one to two, or three or more live births, respectively in 2010.

Data from the 38 areas that reported the number of previous abortions for women obtaining abortions in 2010 indicate that the majority of women (55.4%) had no previous abortions; 36.1% had either one to two previous abortions, and 8.5% had three or more previous abortions (Table 19). Among the 32 reporting areas¶¶¶¶ that provided data for the relevant years of comparison (2001, 2005, 2006, 2009, and 2010), the distribution of abortions by the number of previous abortions was stable, although there was a slight decrease among women who had zero previous abortions and a slight increase among women who had three or more previous abortions. Among the areas included in this comparison, 55.6%, 36.7%, and 7.7% of women had zero, one to two, or three or more previous abortions, respectively, in 2001; by contrast, 54.2%, 36.7%, and 9.1% of women had zero, one to two, or three or more previous abortions, respectively, in 2010.

Age and Marital Status by Race/Ethnicity

In certain reporting areas, abortions that were categorized by maternal race and race/ethnicity were further categorized by maternal age and by marital status (Tables 20 and 21). A consistent pattern existed for abortions by age across all race/ethnicity groups (Table 21), with the smallest percentage of abortions occurring among adolescents aged <15 years (0.3%–0.6%) and the largest percentage occurring among women aged 20–24 years (27.0%–33.5%). A consistent pattern also existed for abortion by marital status across all race/ethnicity groups, with a higher percentage of abortions occurring among women who were unmarried (65.8%–90.6%) than among those who were married (9.4%–34.2%). Although most abortions occurred among unmarried women in all racial/ethnic groups, this percentage was higher for non-Hispanic black women (90.6%) than it was for non-Hispanic white (83.2%) or Hispanic women (83.7%).

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

In certain reporting areas, abortions that were categorized by weeks of gestation were further categorized by maternal age, race, and race/ethnicity (Tables 22 and 23). In every subgroup for these three variables, the largest percentage of abortions was obtained at ≤8 weeks' gestation. However, by age, 45.0% of adolescents <15 years and 56.4% of adolescents 15–19 years obtained an abortion by ≤8 weeks' gestation, whereas 64.0%–73.4% of adult women obtained an abortion by this point in gestation (Figure 3; Table 22). Conversely, 20.3% of adolescents aged <15 years and 11.8% of adolescents 15–19 years obtained an abortion after 13 weeks' gestation, whereas this percentage ranged from 6.6%–8.5% for adult women. By race/ethnicity, 60.1% of non-Hispanic black women obtained an abortion at ≤8 weeks' gestation, whereas 69.3%–71.7% 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.

Among abortions categorized by method type and 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 (73.0%) than at any other stage of gestation. At 9–17 weeks' gestation, curettage accounted for 96.1%–98.2% of all abortions and then decreased to 94.1% of abortions at 18–20 weeks' gestation and 91.2% of abortions at ≥21 weeks' gestation. By contrast, at ≤8 weeks' gestation, early medical abortion accounted for a comparatively high percentage of abortions (26.5%), but at all subsequent points in gestation the use of medications to induce abortions through nonsurgical methods accounted for only 0.7%–3.8% of reported abortions. Throughout gestation, intrauterine instillations and abortions reported in the other methods category accounted for a small percentage (<0.01%–4.1%) of abortions.

Abortion Mortality

Using national data from the Pregnancy Mortality Surveillance System (37), CDC identified eight abortion-related deaths for 2009 (Table 25). 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 all eight deaths were related to legal abortion and none to illegal abortion.

The annual number of deaths related to legal induced abortions has fluctuated from year to year over the past 37 years (Table 25). For example, 12 abortion-related deaths occurred in 1994, four deaths in 1995, and nine deaths in 1996. Because of this variability and the relatively small number of abortion-related deaths every year, national case-fatality rates were calculated for consecutive 5-year periods during 1973–2002 and a 7-year period during 2003–2009. The national legal induced abortion case-fatality rate for 2003–2009 was 0.67 legal induced abortion-related deaths per 100,000 reported legal abortions. This case fatality rate was similar to the rate for the preceding 5-year period (1998–2002) but lower than the case-fatality rate of 2.09 legal induced abortion-related deaths per 100,000 reported abortions for the first 5-year period (1973–1977) immediately following initial nationwide legalization of abortion in 1973. Possible abortion-related deaths that occurred during 2010–2013 are under investigation.

Discussion

For 2010, a total of 765,651 abortions were reported. Of these abortions, 753,065 (98.4%) were from the 46 reporting areas that submitted data every year during 2001–2010, thus providing the information necessary for evaluating trends. These 46 areas had an abortion rate of 14.6 abortions per 1,000 women aged 15–44 years and an abortion ratio of 228 abortions per 1,000 live births. Compared with 2009, this represents a 3% decrease in the total number (from 777,239) and rate (from 15.0 abortions per 1,000 women) of reported abortions. Because of the size of this decrease, combined with the 5% decrease from 2008 to 2009 (35), the overall rate of decrease for both measures was greater during 2006–2010 than during 2001–2005, despite the annual variations that resulted in no net decrease during 2006–2008 (13-15). In contrast to the total number and rate of reported abortions, the ratio of reported abortions to live births was stable (changing only 0.4% from 2009 to 2010). This finding is consistent with the 3% decrease in the total number of births and the fertility rate (live births per 1,000 women aged 15–44 years) from 2009 to 2010 (39), which matches the 3% decrease reported here for the total number of abortions and the abortion rate.

In addition to highlighting changes that occurred among all women of reproductive age, this report underscores important age differences in abortion trends. During 2001–2010, women in their 20s consistently accounted for the majority of abortions (58%–59%) and therefore have contributed substantially to overall changes in abortion rates. Conversely, women aged ≥40 years consistently have accounted for a small percentage of abortions (≤3.5% during 2001–2010) and have had a much smaller contribution to overall abortion trends. Nonetheless, among women aged ≥40 years, abortion rates have shown a small yet persistent increase and abortion ratios remain high. Together with the continuing small proportion of abortions performed later in gestation among women in this age group, which potentially might be completed for maternal medical indications or fetal anomalies, these patterns suggest that unintended pregnancy is a problem that women encounter throughout their reproductive years.

The adolescent abortion trends described in this report are important for monitoring progress that has been made toward reducing pregnancies among adolescents in the United States. During 1990–2008, the pregnancy rate for adolescents aged 15–19 years decreased 40% (5). Although this decrease was associated with significant decreases in rates of live births and abortions, decreases during this period were even greater for abortions than live births (5). Data from this and other recent reports indicate continuing decreases in pregnancies among adolescents, with large decreases occurring both from 2008 to 2009 and from 2009 to 2010 in birth (6% and 10%, respectively) and abortion rates (8% and 9%, respectively) among adolescents aged 15–19 years (35,39,40).

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 non-Hispanic black women can be attributed to higher unintended pregnancy rates and a higher percentage of unintended pregnancies ending in abortion (41,42). Data from some recent reports suggest that differences in measures of abortion between non-Hispanic black women and women of other races have narrowed (10,11). However, this pattern has not been observed in the data reported to CDC for 2010 or in previous years. High abortion rates among Hispanic compared with non-Hispanic white women have been attributed to high pregnancy rates among Hispanic women (41,42). 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 end unintended pregnancies in abortion (42). Differences between non-Hispanic white and Hispanic women in abortion rates changed little from 2007 to 2010, although the difference in abortion ratios widened, with a decrease for non-Hispanic white women and an increase for Hispanic women.

The findings in this report indicate that more women are obtaining abortions earlier in gestation, when the risks for complications are lowest (43–47). Among the areas that reported data every year during 2001–2010, the percentage of abortions performed at ≤8 weeks' gestation increased 10%. 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: from 2001 to 2010, abortions performed at ≤6 weeks' gestation increased 36%, whereas those performed at ≥8 weeks' gestation decreased 10%–23%. However, the shift toward earlier gestational ages was greater from 2001 to 2005 than from 2006 to 2010, suggesting that this trend might have slowed in recent years. Moreover, the overall percentage of abortions performed at ≤13 weeks' gestation changed little during 2001–2010, and findings from this report and other research suggest that delays in obtaining an abortion are more common among certain groups of women (48,49). Given the small but persistent percentage of women who obtain abortions at >13 weeks' gestation, a greater understanding is needed of the factors that cause delays in obtaining abortions (48,50–52).

The trend of obtaining abortions earlier in pregnancy, although not observed equally among all subgroups of women, has been facilitated by changes in abortion practices. Research conducted in the United States during the 1970s indicated that surgical abortion procedures performed at ≤6 as compared with 7–12 weeks' gestation were less likely to result in successful termination of the pregnancy (53). However, subsequent advances in technology (e.g., improved transvaginal ultrasonography and sensitive pregnancy tests) have allowed very early surgical abortions to be performed with high effectiveness rates exceeding 97% (43,54–56). Likewise, the development of medical abortion regimens has allowed for abortions to be performed very early in gestation, with completion rates for regimens that combine mifepristone and misoprostol reaching 96%–98% (57). In 2010, 65.9% of abortions were performed at ≤8 weeks' gestation and thus the women receiving these abortions were eligible for early medical abortion on the basis of gestational age; 26.5% of these abortions at ≤8 weeks' gestation and 17.7% of all abortions were reported as early medical abortions. Moreover, the use of early medical abortion has increased substantially since the U.S. Food and Drug Administration approval of mifepristone: from 2001 to 2010, the percentage of all reported abortions accounted for by this method increased approximately 400%. Furthermore, whereas the largest increases were observed after the initial years of approval (58), the proportional use of this method has continued to increase: from 2009 to 2010, the percentage of all abortions reported as early medical abortion increased 13%, as compared with the 10% increase that occurred from 2008 to 2009 (35).

The annual number of legal induced abortions has fluctuated from year to year over the past 37 years. Because of this variability and the relatively small number of abortion-related deaths every year, national case-fatality rates could only be calculated for consecutive 5-year periods during 1973–2002 and a 7-year period during 2003–2009. The national legal induced abortion case-fatality rate for 2003–2009 was similar to the case fatality rate for the preceding 5-year period of 1998–2002, but much lower than the case fatality year for the period of 1973–1978 that immediately followed nationwide legalization of abortion in 1973.

Limitations

The findings in this report are subject to at least four limitations. First, because reporting requirements are established by the individual reporting areas (17), the collection of data varies, and CDC is unable to obtain the total number of abortions performed in the United States. During the period covered by this report, the total annual number of abortions recorded by CDC was 65%–69% of the number recorded by the Guttmacher Institute (12,59), which uses numerous active follow-up techniques to increase the completeness of the data obtained through its periodic national census of abortion providers (12). Although most reporting areas collect and send abortion data to CDC, this information is given to CDC voluntarily. Consequently, during 2001–2010, six of the 52 reporting areas did not provide CDC data on a consistent annual basis, and for 2010, 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 (16). As a result, the abortion numbers these areas report to CDC are 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 (60). Consequently, several other reporting areas tend to 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 follow the technical standards and guidance CDC developed in collaboration with NAPHSIS. 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) (60). 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 percentage distributions for most characteristics that are nearly identical to the percentage distributions reported by CDC. The one exception is the percentage distribution of abortions by race/ethnicity. In particular, the percentage of abortions accounted for by non-Hispanic black women is higher in this report than the percentage based on a recent nationally representative survey of abortion patients (10). Similarly, the greater decrease in abortion rates for non-Hispanic black women compared with women of other racial/ethnic groups based on nationally representative survey data (11) is not supported by the data reported to CDC. 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 because 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 to CDC, or have not reported cross-classified race/ethnicity data (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.

Similar to the case for race/ethnicity, the absence of medical abortion as a specific category on the reporting form used by some states (16) might reduce the precision of CDC's estimates of the use of this method relative to other abortion techniques. Furthermore, even in states with medical abortion on their reporting form, it is possible that this method is disproportionately undercounted: a higher percentage of the abortions provided in physician's offices and smaller caseload facilities are medical abortions (12,61), and these practices might be difficult to locate in the wider medical community without active surveillance efforts (61). Nonetheless, a recent comparison of CDC data with mifepristone sales data¶¶¶¶¶ suggests that CDC's Abortion Surveillance System accurately describes the use of medical abortion relative to other abortion methods in the United States (62).

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. Thus, the available population (23-32) and birth data (33), which are organized by the states in which women live, might differ in some cases from the population of women seeking abortions in a given reporting area. 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 geographic occurrence. However, in 2010, CDC was unable to identify the reporting area, territory, or country of residence for 11.4% of reported abortions.

Finally, adjustments for socioeconomic status cannot be made because CDC does not collect abortion data by 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. Although pregnancy intentions are complex and difficult to assess (63-71), abortion surveillance 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) (5,72).

According to the most recent national estimates, 18% of all pregnancies in the United States end in abortion (5). Multiple factors are known to influence the incidence of abortion, including the availability of abortion providers (12,73-75); state regulations, such as mandatory waiting periods (76), parental involvement laws (77), and legal restrictions on abortion providers (78); increasing acceptance of nonmarital childbearing (79,80); shifts in the racial/ethnic composition of the U.S. population (81,82); and changes in the economy and the resulting impact on fertility preferences and access to health-care services, including contraception (83,84). However, despite these multiple influences, given that unintended pregnancy precedes nearly all abortions (22),****** efforts to reduce the incidence of abortion need to focus on helping women avoid pregnancies that they do not desire.

Providing women and men 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 improve contraceptive use and reduce the number of unintended pregnancies 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 (85–87). However, data from the 2002 and 2006–2010 NSFGs indicate that contraceptive use among women at risk for unintended pregnancy has decreased (86,88). Moreover, although use of the most effective forms of reversible contraception (i.e., intrauterine devices and hormonal implants), which are as effective as sterilization at preventing unintended pregnancy (89), has increased (88,90), use of these methods in the United States remains among the lowest of any developed country (90), and no additional progress has been made toward reducing unintended pregnancy (41,42,71). Research has shown that providing contraception for women at no cost to them increases use of the most effective methods and can reduce abortion rates (91,92). Removing cost as one barrier for women to the use of the most effective contraceptive methods might be an important way to reduce the number of unintended pregnancies and consequently the number of abortions that are performed in the United States.

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