Abortion Surveillance: Preliminary Analysis - United States, 1997

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For 1997, CDC compiled data about legal induced abortions from the 50 states, New York City, and the District of Columbia. The total number of legal induced abortions was available from all reporting areas; however, not all these areas collected information about the characteristics of women who obtained abortions. This report presents preliminary data for 1997; final 1997 abortion data will be published during summer 2000.

In 1997, 1,184,758 legal induced abortions were reported to CDC (Table 1), a decrease of 3.0% from 1996 (1). The number of live births also decreased slightly (0.3% decrease) during the same period (2). From 1996 to 1997, the number of reported abortions decreased in 34 of 52 reporting areas. The national abortion ratio (number of legal abortions per 1000 live births reported by all reporting areas) decreased from 314 in 1996 to 305 in 1997 (Table 1), and the national abortion rate (number of legal abortions per 1000 women aged 15-44 years) remained at 20. Consistent with previous years, approximately 92% of women who had legal induced abortions were residents of the state in which the procedure was performed. Women who obtained legal abortions in 1997 were predominately white and unmarried. As in 1996, approximately 20% of women who obtained a legal abortion in 1997 were aged less than or equal to 19 years; 32% were aged 20-24 years.

Curettage (suction and sharp) remained the primary abortion procedure (98%); 18 reporting areas submitted information about abortions performed by medical (nonsurgical) procedures*. In 1997, 16 reporting areas reported 2988 medical procedures, and two states reported that medical procedures were included in the "other" category. As in previous years, more than half (approximately 55%) of legal abortions were performed during the first 8 weeks of gestation; 18% were at less than or equal to 6 weeks; 18% at 7 weeks; and 20% at 8 weeks. Approximately 88% were performed during the first 12 weeks of pregnancy.

Reported by: Surveillance Unit, Statistics and Computer Resources Br, Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.

Editorial Note:

In the United States during 1980-1990, the number of legal induced abortions varied annually by less than or equal to 5% and increased overall by 10% (Table 1). The reported number of legal induced abortions was highest in 1990. Since that year, the number of abortions has declined each year by 2%-5%, except 1995-1996, when the number of abortions increased by 0.9%. The number of abortions reported to CDC for 1997 declined from 1996 and is the lowest recorded number since 1978 (4).

The national legal induced abortion rate indicates the number of abortions per 1000 women of reproductive age in a given year. During 1972-1980, the national legal induced abortion rate increased each year; during 1980-1991, the rate remained stable and declined during 1991-1995. The 1997 abortion rate of 20 per 1000 women of reproductive age (aged 15-44 years) remained unchanged from 1995 and was the lowest rate recorded since 1975 (5).

The national ratio of legal induced abortions to live births indicates the number of abortions per 1000 live births. The national abortion ratio steadily declined each year from 1987 to 1995; in 1996, a slight increase in the ratio occurred; in 1997, the abortion ratio decreased and was at its lowest recorded level since 1975 (5). Factors that might have contributed to the decline include a reduced number of unintended pregnancies, attitude changes concerning the decision to have an abortion or to carry a pregnancy to term, and reduced access to abortion services (6-8).

The decline in the abortion ratios also might be attributed to a shift in the age distribution of reproductive-aged women obtaining abortions. Although the actual number of women of reproductive age has increased by 2% since 1990, the proportion who are older (i.e., in later, less fertile reproductive years) also has increased. During 1990-1997, the percentage of reproductive-aged women in the highest fertility age group (less than 30 years) declined from 49% to 46% (Bureau of the Census, unpublished data, 1999), and the percentage in the lowest fertility age group (women aged 35-44 years) increased from 33% to 37% (2).

For the first time in this report, medical (nonsurgical) procedures are included. Since the mid-1990s, medications (e.g., methotrexate and misoprostol) have been used by clinical practitioners to perform early medical abortions (9). In 1997, the U.S. Standard Report of Induced Termination of Pregnancy, published by CDC's National Center for Health Statistics, was revised to include "Medical (Nonsurgical)," a new procedure category (3). In 1997, 18 states, New York City, and the District of Columbia included medical abortion procedures on their reporting forms. For the same year, 16 reporting areas submitted information to CDC about the number of performed medical abortions. However, the number reported to CDC may be an undercount; other researchers have estimated that approximately 4300 medical procedures were performed during the first half of 1997 (7). During 1994-1995 in the United States, approximately 2000 women aged greater than 18 years participated in clinical trials testing mifepristone (10), a medication the Food and Drug Administration (FDA) has found "approvable" for use as an abortifacient (FDA, personal communication, 1999). Researchers expect that medical induced abortions will become more widespread if mifepristone is approved for use (7).

Since 1992, most reporting areas have reported abortions by gestational age in weeks of gestation for abortions performed at less than or equal to 8 weeks. As new medical methods are introduced and used for terminating pregnancies primarily at less than 8 weeks of gestation, these data will continue to assist in monitoring trends in legal abortions.

During 1997, the total numbers of legal induced abortions were available for each of the 52 reporting areas. However, approximately 32% of abortions were reported from states that in 1997 did not have annual centralized reporting of abortions (three states) or from states whose health departments could not provide information about characteristics (e.g., age or race) of women obtaining legal abortions (two states). To track efforts to prevent unintended pregnancy and changes in abortion practice, each state needs an accurate and ongoing assessment of abortion (including the number and characteristics of women obtaining legal abortions).

Previously published MMWRs that include statistical and epidemiologic information about abortion are available on the CDC World-Wide Web site, http://www.cdc.gov/mmwr (1).

References

1. Koonin LM, Strauss LT, Chrisman CE, Montalbano MA, Bartlett LA, Smith JC. Abortion surveillance, United States, 1996. In: MMWR surveillance summaries (July 1999). MMWR 1999;48(no. SS-4).
2. Ventura SJ, Martin JA, Curtin SC, Mathews TJ. Births: final data for 1997. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, National Center for Health Statistics,1999; DHHS publication no. (PHS)99-1120. (Monthly vital statistics report;vol 47, no. 18).
3. CDC. Handbook on the reporting of induced termination of pregnancy (revised instructions and reporting form). Hyattsville, Maryland: US Department of Health and Human Services, CDC, 1997:1-18.
4. CDC. Abortion surveillance-1978. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, CDC, 1980.
5. CDC. Abortion surveillance-1975. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, CDC, 1977.
6. Abma J, Chandra A, Mosher W, Peterson L, Piccinino L. Fertility, family planning, and women's health: new data from the 1995 National Survey of Family Growth. Vital Health Stat 1997;23:1-114.
7. Henshaw SK. Abortion incidence and services in the United States, 1995-1996. Fam Plann Perspect 1998;30:262-3,287.
8. Henshaw SK, Kost K. Abortion patients in 1994-1995. Fam Plann Perspect 1994;28:140-7,158.
9. Creinin MD, Vittinghoff E, Schaff E, Klaisle C, Darney PD, Dean C. Medical abortion with oral methotrexate and vaginal misoprostol. Obstet Gynecol 1997;90:611-6.
10. Winikoff B, Ellertson C, Elul B, Sivin I. Acceptability and feasibility of early pregnancy termination by mifepristone-misoprostol. Results of a large multicenter trial in the United States. Arch Fam Med 1998;7:360-6.

* Medical abortions are nonsurgical procedures involving the administration of medication(s) to induce an abortion and are most frequently performed early in the first trimester of pregnancy (3).

TABLE 1. Reported number of legal induced abortions, abortion ratios,* abortion rates,^† and characteristics of women who obtained legal induced abortions, by year--United States, selected years, 1972-1997

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