Abortion Surveillance, 1986-1987

Lisa M. Koonin, M.N., M.P.H.* Hani K. Atrash, M.D., M.P.H.** Jack C. Smith, M.S.* Merrell Ramick* *Statistics and Computer Resources Branch **Pregnancy and Infant Health Branch Division of Reproductive Health Center for Chronic Disease Prevention and Health Promotion Summary

Since 1980, the number of legal abortions reported to CDC has remained fairly stable, varying each year by less than 3%. In 1986, 1,328,112 abortions were reported; in 1987, that number increased by approximately 2% to 1,353,671. The abortion ratio for 1986 was 354 legally induced abortions per 1,000 live births; the ratio for 1987 was 356 per 1,000. The national abortion rate was 23/1,000 females ages 15-44 years for 1986 and 24/1,000 females ages 15-44 years in 1987. Abortion ratios were higher among women of black and other minority races and among women less than 15 years of age. Women undergoing legally induced abortions tended 1) to be young, white, and unmarried, 2) to have had no previous live births, and 3) to be having the procedure for the first time. In 1987, approximately half of all abortions were performed before the eighth week of gestation, and greater than 85% were performed during the first trimester of pregnancy ( less than 13 weeks of gestation). INTRODUCTION

In 1969, CDC began abortion surveillance to document the number and characteristics of women obtaining abortions and to assist efforts to eliminate preventable causes of morbidity and mortality associated with abortions. This report presents abortion data reported to CDC for 1986 and 1987. METHODS

For 1986 and 1987, CDC received data from 52 reporting areas: 50 states, New York City, and the District of Columbia. Total numbers of abortions were available from all reporting areas, most of which provided information on the characteristics of women obtaining abortions. Central health agencies* reported data for 43 areas in 1986 and 45 areas in 1987; hospitals and other medical facilities reported data for the other nine reporting areas in 1986 and the other seven in 1987. Data are reported by state of occurrence unless otherwise noted.

National statistics for 1986, 1987, and selected previous years are presented in a summary table (Table 1) and in Table 2. Percentage distributions in Table 1 include data from all areas reporting a given characteristic and exclude all unknown values. State-specific characteristics of women obtaining abortions in 1986 and 1987 are presented in Tables 3-12; overall tabulations of selected characteristics are presented in Tables 13-20. RESULTS

In 1986, 1,328,112 legal abortions were reported to CDC--0.03% less than the number reported for the previous year (1). In 1987, the number increased to 1,353,671, an increase of approximately 2% from the 1986 figure. The national abortion rate decreased from 24 abortions/1,000 women ages 15-44 in 1985 to 23/1,000 in 1986 and increased again to 24/1,000 in 1987. The abortion ratio remained stable from 1985 to 1986, at 354 abortions/1,000 live births, and then increased to 356/1,000 in 1987 (Table 1, Figures 1-3).

In 1986 and 1987, as in previous years, the largest numbers of abortions were performed in California, New York City, and Texas; the smallest numbers of abortions were performed in Wyoming, Alaska, and South Dakota (1,2). For women whose state of residence was known, approximately 92% had the abortion procedure done within their state of residence. For both years, the percentage of abortions obtained by out-of-state residents ranged from approximately 50% in the District of Columbia to less than 1% in Alaska (Tables 3 and 4). Data on the percentage of abortions obtained by out-of-state residents are not available for five reporting areas in 1986 and for seven reporting areas in 1987.

In 1986, 37 states, the District of Columbia, and New York City reported legal abortions by age; in 1987, 39 states, the District of Columbia, and New York City reported those figures. In both years, women 20-24 years of age had approximately 33% of all abortions, whereas women less than 15 years of age had approximately 1% (Tables 5 and 6). The abortion ratio was highest for women less than 15 years of age and second highest for women 15-19 years of age. The abortion ratio for women less than 15 years of age was 1,163 abortions/1,000 live births in 1986 and 1,275/1,000 in 1987; the ratio for women 15-19 years of age was 650/1,000 in 1986 and 668/1,000 in 1987 (Figure 4). Although teenagers' abortion ratios were the highest during 1986-1987, the proportion of legal abortions they obtained continued to remain stable. Teenagers had 25% of all legal abortions in 1986 and 26% in 1987. Among that age group, the abortion ratio was lowest among 19-year-olds and highest among those less than 15 years of age (Tables 7 and 8).

In 1986 and 1987, approximately 49% of reported legal abortions were performed before 8 weeks of gestation, and 87% were done at or before 12 weeks of gestation (Tables 9 and 10). Four percent of the abortions for those 2 years were performed at 16-20 weeks of gestation, and less than 1% at greater than or equal to 21 weeks of gestation.

In both years, approximately 96% of reported legal abortions were performed by curettage (Tables 11 and 12). In less than 2%, the method was intrauterine saline or prostaglandin instillation.

In 1986 and 1987, almost two-thirds of women obtaining legal abortions were white; this finding continued a previously noted trend (1,2) (Table 13). The abortion ratio, however, was higher for black women and women of other minority races than for white women: 488 versus 269 abortions/1,000 live births in 1986 and 500 versus 267 abortions/1,000 in 1987.

The percentage of women undergoing legal abortions who were unmarried fell from approximately 80% in 1985 to 73% in 1986, and then to almost 70% in 1987. The abortion ratio was approximately 10 times higher for unmarried women than for married women: 958 versus 102 abortions/1,000 live births in 1986 and 1,019 versus 96/1,000 in 1987 (Table 14).

In both years, approximately 53% of the women obtaining legal abortions had had no previous live births, and approximately 88% had had two or fewer live births (Table 15). In both 1986 and 1987, the abortion ratio was highest for women who had had no live births and lowest for women who had had one live birth. Approximately 55% of women obtaining abortions in 1986 and 1987 had the procedure for the first time, whereas approximately 14% had had at least two abortions (Table 16).

When the proportions of women undergoing abortions were analyzed by age group and marital status, few differences were reported between white women and women of black and other minority races (Tables 17 and 18). However, the proportion of black and other minority women less than 15 years of age having abortions was approximately twice that of white women in this age group.

When analyzed by gestational age, approximately 99% of abortions at less than or equal to 12 weeks of gestation were performed by curettage (Tables 19 and 20). After 12 weeks of gestation, the most common procedure was curettage, which was usually reported as dilatation and evacuation (D&E). Most intrauterine instillations involved the use of saline and were performed at greater than or equal to 16 weeks of gestation. DISCUSSION

From 1970 to 1982, the reported number of legal abortions in the United States increased every year (Figure 1); the largest percentage increase occurred during the period 1970-1972. From 1976 to 1982, this annual increase declined continuously, reaching a low of 0.2% for 1981-1982. However, since 1983, the numbers, as well as the rates and ratios of abortion, have remained relatively stable, with small ( less than 3%) year-to-year fluctuations (1).

The abortion ratio increased each year from 1970 to 1980 and has remained relatively stable since 1980 (Figure 2). In 1986, the abortion ratio was 354.2 abortions/1,000 live births, and in 1987 it increased slightly to 356.1. The abortion rate also increased each year through 1980, when it reached 25 abortions/1,000 females ages 15-44. Since that time, the rate has remained stable, fluctuating from 23 to 24 abortions/1,000 women ages 15-44 (Figure 3).

The numbers of legal abortions reported to CDC in 1986 and 1987 were probably lower than the numbers actually performed. These numbers are based primarily on information provided by central health agencies, whose totals are often lower than those obtained by direct surveys of abortion providers (3). For example, in 1987, the total number of abortions reported by CDC was approximately 13% lower than that reported by the Alan Guttmacher Institute, a private organization that obtains information directly from abortion providers (4).

In each year from 1975 through 1985, the proportion of women obtaining an abortion in their state of residence increased from 89% in 1975 to 93% in 1983 and has remained at approximately 92% since 1984.

In 1972, the women obtaining abortions were almost evenly distributed among three age groups: less than or equal to 19 years of age; 20-24 years of age; and greater than or equal to 25 years of age. Between 1972 and 1987, the proportion of abortions obtained by teenagers decreased steadily from 33% to 26%. Upward shifts in the age of women in the population may account for the continuing greater proportion, in 1986 and 1987, of abortions obtained by women greater than or equal to 20 years of age (5,6).

We observed several other trends--not necessarily related to each other--concerning the women who obtained abortions between 1972 and 1987. During the period 1972-1985, the proportion of women obtaining abortions who were unmarried increased steadily from 70% to 81%. In 1986, the proportion of unmarried women decreased to 73% and further declined in 1987 to 70%. The percentages of black women and women of other minority races increased from 23% in 1972 to 32% in 1987, and the proportion of women with one or no previous live births increased from 67% to 73% during the same period. The percentage distribution by gestational age has been stable since 1977.

In 1986 and 1987, the trend continued for a smaller proportion of women to obtain abortions for the first time; 87% of women in 1974 and 55% of women in 1987 had had no previous abortions. During this 13-year period, the percentage of women who had previously had one induced abortion increased from 11% to 25%, the percentage of those who had had two induced abortions increased from 1.5% to 9.6%, and the percentage of those who had had three or more induced abortions increased from 0.4% to 4.7%. These increases probably reflect the ongoing availability of abortions, the increasing number of women at risk of having a repeat abortion, and the fact that women who have had an abortion are more likely to have another (7,8).

Between 1972 and 1987, the percentage of abortions performed by curettage increased from 89% to 97%. Surveillance during the same period showed declines in the percentages of abortions performed by intrauterine instillation (from 10% to 1%) and by hysterectomy and hysterotomy (from 0.6% to 0.1%).

Between 1975 and 1987, the percentage of second-trimester abortions performed by D&E increased from 33% to 76%, whereas the percentage of second-trimester abortions performed by intrauterine instillation decreased from 57% to 10%. This increasing use of D&E most likely reflects improved technology and physicians' awareness that a lower risk of complications is associated with D&Es than with instillation procedures (9).

References

1. CDC. Abortion surveillance, United States, 1984-1985. In: CDC Surveillance Summaries, September 1989. MMWR 1989;38(no. SS-2):11-45.

2. CDC. Abortion Surveillance, 1982-1983. In: CDC Surveillance Summaries, February 1987. MMWR 1987;36(no. 1SS):11-42.

3. Atrash HK, Lawson HW, Smith JC. Legal abortion in the US: trends and mortality. Contemp OB/GYN 1990;35:58-69.

4. Henshaw SK, VanVort J. Abortion services in the United States, 1987 and 1988. Fam Plann Perspect 1990;22:102-8.

5. Bureau of Census. Estimates of population of the United States by age, sex, and race: 1980 to 1987. Washington, DC: US Department of Commerce, 1988; current population reports, series P-25, no. 1022:13-7.

6. Tietze C. Repeat abortion--why more? Fam Plann Perspect 1978;10:286-8.

7. Tietze C, Jain A. The mathematics of repeat abortion: explaining the increase. Stud Fam Plann 1978;9:294-9.

8. Tietze C, Bougaarts J. Repeat abortion in the United States: new insights. Stud Fam Plann 1982;13:373-9.

9. Cates W Jr, Schulz KF, Grimes DA, et al. Dilatation and evacuation procedures and second-trimester abortion: the role of physician skill and hospital setting. JAMA 1982;248:559-63. *Includes state health departments and health departments from New York City and the District of Columbia.

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