Abortion surveillance--United States, 1997

PROBLEM/CONDITION

In 1969, CDC began abortion surveillance to document the number and characteristics of women obtaining legal induced abortions, to monitor unintended pregnancy, and to assist efforts to identify and reduce preventable causes of morbidity and mortality associated with abortions.

REPORTING PERIOD COVERED

This report summarizes and reviews information reported to CDC regarding legal induced abortions obtained in the United States in 1997.

DESCRIPTION OF SYSTEM

For each year since 1969, CDC has compiled abortion data by state where the abortion occurred. The data are received from 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City.

RESULTS

In 1997, a total of 1,186,039 legal abortions were reported to CDC, representing a 3% decrease from the number reported for 1996. The abortion ratio was 306 legal induced abortions per 1,000 live births, and since 1995, the abortion rate has remained at 20 per 1,000 women aged 15-44 years. The availability of information about characteristics of women who obtained an abortion in 1997 varied by state and by the number of states reporting each characteristic. The total number of legal induced abortions by state is reported by state of residence and state of occurrence; characteristics of women obtaining abortions in 1997 are reported by state of occurrence. Women who were undergoing an abortion were more likely to be young (i.e., aged < 25 years), white, and unmarried; approximately one half were obtaining an abortion for the first time. More than one half of all abortions for which gestational age was reported (55%) were performed at < or = 8 weeks of gestation, and 88% were performed before 13 weeks. Overall, 18% of abortions were performed at the earliest weeks of gestation (< or = 6 weeks), 18% at 7 weeks of gestation, and 20% at 8 weeks of gestation. From 1992 through 1997, increases have occurred in the percentage of abortions performed at the very early weeks of gestation. Few abortions were provided after 15 weeks of gestation--4% of abortions were obtained at 16-20 weeks, and 1.4% were obtained at > or = 21 weeks. A total of 19 reporting areas submitted information regarding abortions performed by medical (nonsurgical) procedures, comprising < 1% of procedures reported by all states. Younger women (i.e., aged < or = 24 years) were more likely to obtain abortions later in pregnancy than were older women.

INTERPRETATION

From 1990 through 1995, the number of abortions declined each year; in 1996, the number increased slightly, and in 1997, the number of abortions in the United States declined to it lowest level since 1978.

PUBLIC HEALTH ACTIONS

The number and characteristics of women who obtain abortions in the United States should continue to be monitored so that trends in induced abortion can be assessed and efforts to prevent unintended pregnancy can be evaluated.

Are interpregnancy intervals between consecutive live births among black women associated with infant birth weight?

OBJECTIVES

The purpose of this study was to determine whether the length of interpregnancy intervals between consecutive live births among Black women had any significant effect on mean birth weight as had previously been reported in another study.

DESIGN

We examined a sample (1,048 women, 66% of study participants) from a study of non-Hispanic Black women whose infants were born at a large, inner-city, public hospital in Georgia from October 1988 through August 1990. Data were evaluated for the 494 women whose current and immediately previous pregnancies ended in the birth of a live infant weighing 500 grams or more.

METHODS

Linear regression and analysis of covariance models were developed.

RESULTS

The median interpregnancy interval was 15 months (range 1 to 207 months), with 19 (4%) of the women having intervals of less than 3 months. After adjustment for parity, gestational age (in weeks), and smoking status, the mean birth weight associated with an interpregnancy interval of three or more months was 3,106 grams, 215 grams greater than that for an interval of less than three months (P = .06).

CONCLUSIONS

Although longer birth spacing has been associated with certain positive social and health effects, the population attributable effect on infant birth weight may not be very significant.

The decline in US teen pregnancy rates, 1990-1995

OBJECTIVES

Estimate pregnancy, abortion, and birth rates for 1990 to 1995 for all teens, sexually experienced teens, and sexually active teens. DESISN: Retrospective analysis of national data on pregnancies, abortions, and births. Participants. US women aged 15 to 19 years.

OUTCOME MEASURES

Annual pregnancy, abortion, and birth rates for 1990 to 1995 for women aged 15 to 19 years, with and without adjustments for sexual experience (ever had intercourse), and sexual activity (had intercourse within last 3 months).

RESULTS

Approximately 40% of women aged 15 to 19 years were sexually active in 1995. Teen pregnancy rates were constant from 1990 to 1991. From 1991 to 1995, the annual pregnancy rate for women aged 15 to 19 years decreased by 13% to 83.6 per 1000. The percentage of teen pregnancies that ended in induced abortions decreased yearly; thus, the abortion rate decreased more than the birth rate (21% vs 9%). From 1988 to 1995, the proportion of sexually experienced teens decreased nonsignificantly.

CONCLUSIONS

After a 9% rise from 1985 to 1990, teen pregnancy rates reached a turning point in 1991 and are now declining. Physicians should counsel their adolescent patients about responsible sexual behavior, including abstinence and proper use of regular and emergency contraception.

Abortion surveillance--United States, 1995

CONDITION

Since 1990 (i.e., the year in which the number of abortions was highest), the annual number of abortions in the United States has decreased by 15%.

REPORTING PERIOD COVERED

This report summarizes and reviews information reported to CDC regarding legal induced abortions obtained in the United States during 1995.

DESCRIPTION OF SYSTEM

For each year since 1969, CDC has compiled abortion data received from 52 reporting areas: 50 states, the District of Columbia, and New York City.

RESULTS

In 1995, a total of 1,210,883 legal abortions were reported to CDC, representing a 4.5% decrease from the number reported for 1994. The abortion ratio was 311 legal induced abortions per 1,000 live births, and the abortion rate was 20 per 1,000 women aged 15-44 years, the lowest ratio and rate recorded since 1975. Women who were undergoing an abortion were more likely to be young, white, and unmarried; most were obtaining an abortion for the first time. Approximately half of all abortions (54%) were performed at < or =8 weeks of gestation, and approximately 88% were performed before 13 weeks. Approximately 16% of abortions were performed at the earliest weeks of gestation (< or =6 weeks), approximately 17% at 7 weeks of gestation, and approximately 21% at 8 weeks of gestation. Few abortions were provided after 15 weeks of gestation -- approximately 4% of abortions were obtained at 16-20 weeks, and 1.4% were obtained at > or =21 weeks. Younger women (i.e., women aged < or =24 years) were more likely to obtain abortions later in pregnancy than were older women.

INTERPRETATION

Since 1990, the number of abortions has declined each year. Since 1987, the abortion-to-live-birth ratio has declined; in 1995, it was the lowest recorded since 1975. This decrease in the abortion ratio reflects a trend that a lower proportion of pregnant women obtain induced abortion.

ACTIONS TAKEN

The number and characteristics of women who obtain abortions in the United States should continue to be monitored so that trends in induced abortion can be assessed, efforts to prevent unintended pregnancy can be evaluated, and the preventable causes of morbidity and mortality associated with abortions can be identified and reduced.

Cigarette smoking as a risk factor for ectopic pregnancy

OBJECTIVE

Our purpose was to assess the risk of ectopic pregnancy among women who smoke cigarettes.

STUDY DESIGN

We used data from a case-control study of ectopic pregnancy conducted from October 1988 to August 1990 at an inner-city hospital in Georgia. Cases were 196 non-Hispanic black women with a surgically confirmed ectopic pregnancy. Controls were non-Hispanic black women who had delivered either a live or a stillborn infant weighing at least 500 gm (n = 882) or who were pregnant and seeking an induced abortion (n = 237).

RESULTS

After we adjusted for parity, douching history, history of infertility, and age, the odds ratio for ectopic pregnancy was 1.9 (95% confidence interval 1.4 to 2.7) for women who smoked during the periconception period compared with women who did not smoke at that time. After stratification by the amount of daily smoking during the periconception period, the odds ratio rose from 1.6 (95% confidence interval 0.9 to 2.9) for women who smoked 1 to 5 cigarettes to 1.7 (95% confidence interval 1.1 to 2.8) for women who smoked 6 to 10 cigarettes to 2.3 (95% confidence interval 1.3 to 4.0) for women who smoked 11 to 20 cigarettes, and to 3.5 (95% confidence interval 1.4 to 8.6) for women who smoked >20 cigarettes per day.

CONCLUSION

In this inner-city population, cigarette smoking was an independent, dose-related risk factor for ectopic pregnancy among black women. The public health and medical care communities should inform the public of this additional risk associated with cigarette smoking and intensify intervention strategies to reduce cigarette smoking among women of reproductive age.

Abortion surveillance--United States, 1993 and 1994

CONDITION

From 1991 through 1994, the number of legal induced abortions reported to CDC declined each year by < or =5% from the number reported for the preceding year.

REPORTING PERIOD COVERED

This report summarizes and reviews information reported to CDC regarding legal induced abortions obtained in the United States during 1993 and 1994. This analysis also includes recently reported abortion-related deaths that occurred during 1991.

DESCRIPTION OF SYSTEM

For each year since 1969, CDC has compiled abortion data received from 52 reporting areas: 50 states, the District of Columbia, and New York City.

RESULTS

In 1993, 1,330,414 legal abortions were reported to CDC, representing a 2.1% decrease from the number reported for 1992; in 1994, 1,267,415 abortions were reported, representing a 4.7% decrease from the number for 1993. In 1993 and 1994, the abortion ratio was 334 and 321 legal induced abortions per 1,000 live births, respectively. In 1993, the abortion rate was 22 per 1,000 women aged 15-44 years; in 1994, this rate declined to 21 per 1,000 women. Women who were undergoing an abortion were more likely to be young, white, and unmarried; most were obtaining an abortion for the first time. More than half of all abortions (52%-54%) were performed at < or =8 weeks of gestation, and approximately 88% were before 13 weeks. Approximately 15%-16% of abortions were performed at < or =6 weeks of gestation, 16% were performed at 7 weeks, and 22% at 8 weeks. Younger women (i.e., women aged < or =19 years) were more likely to obtain abortions later in pregnancy than were older women. In 1991, 12 women died as a result of induced abortion: 11 of these deaths were related to legal abortion and one to illegal abortion. During 1991, the case-fatality rate of legal induced abortion was 0.8 abortion-related deaths per 100,000 legal induced abortions.

INTERPRETATION

Since 1990, the number of abortions has declined each year. Since 1987, the abortion-to-live-birth ratio also has declined; in 1994, it was the lowest recorded since 1977. This decrease in the abortion ratio reflected the lower proportion of pregnant women who obtained an induced abortion. As in previous years, deaths related to legal induced abortions occurred rarely (i.e., approximately one death per 100,000 legal induced abortions).

ACTIONS TAKEN

The number and characteristics of women who obtain abortions in the United States should continue to be monitored so that trends in induced abortion can be assessed, efforts to prevent unintended pregnancy can be evaluated, and the preventable causes of morbidity and mortality associated with abortions can be identified and reduced.

Vaginal douching and the risk of ectopic pregnancy among black women

OBJECTIVE

Our goal was to determine whether vaginal douching was associated with ectopic pregnancy among black women and whether specific douching behaviors were associated with differences in risk.

STUDY DESIGN

We analyzed data from a case-control study of ectopic pregnancy conducted between October 1988 and August 1990 at a major public hospital in Atlanta, Georgia. Case subjects were 197 black women with surgically confirmed ectopic pregnancies; the control group included 882 black women who were delivered of live or stillborn infants and 237 black women who were seeking to terminate a pregnancy.

RESULTS

The adjusted odds ratio for ectopic pregnancy associated with ever having douched was 3.8 (95% confidence interval 1.6 to 8.9). The risk increased with increasing number of years of douching at least once per month. No douching behavior was found to be without risk; even women who douched for routine cleanliness were at increased risk of ectopic pregnancy.

CONCLUSIONS

Vaginal douching is a modifiable behavior that may greatly increase a woman's risk of ectopic pregnancy.

The relation between induced abortion and ectopic pregnancy

OBJECTIVE

To determine whether having had one or more induced abortions increases a woman's risk of having an ectopic pregnancy.

METHODS

We conducted a case-control study of all women admitted to a major metropolitan hospital in Georgia with a surgical diagnosis of ectopic pregnancy during the period of October 1988 to August 1990. Controls were randomly selected from women seeking an induced abortion or delivering an infant at the same hospital. After exclusions, this analysis included 182 cases and 1056 controls. Stratified analysis and unconditional logistic regression were used to control for confounding and to estimate the relative risks.

RESULTS

Approximately 90% of cases and controls were non-Hispanic, black women; 34% of the cases and 36% of the controls reported a history of induced abortion. The crude odds ratio for having an ectopic pregnancy associated with a history of induced abortion was 0.9 (95% confidence interval 0.6, 1.3). The odds ratio remained the same after adjusting for selected confounding variables and stratifying by the number of induced abortions, gestational age at the time of abortion, place where the abortion was performed, and the woman's report of medical complications of the abortion.

CONCLUSION

We found no evidence that having one or more induced abortions increases a woman's risk of having an ectopic pregnancy.

Pregnancy, abortion, and birth rates among US adolescents--1980, 1985, and 1990

OBJECTIVE

To analyze pregnancy, abortion, and birth rates among US adolescent girls in 1980, 1985, and 1990.

DESIGN

Retrospective analysis of trends in data on pregnancies, abortions, and births.

POPULATION

US adolescent girls aged 13 to 19 years.

MAIN OUTCOME MEASURES

Pregnancy, abortion, and birth rates (with and without adjustment for sexual experience) among teenaged girls aged 15 to 19 years and girls under 15 years.

RESULTS

Although pregnancy rates among all teenaged girls 15 to 19 years old remained fairly stable from 1980 to 1985, they increased by 9% during the last half of the decade, totaling 95.9 pregnancies per 1000 teenaged girls 15 to 19 years old by 1990. Because rates of sexual experience increased even faster, pregnancy rates among sexually experienced teens aged 15 to 19 actually declined between 1980 and 1990 by approximately 8%. Abortion rates among these teens remained stable during the 1980s, with 35.8 and 36.0 abortions per 1000 in 1980 and 1990, respectively. As with overall pregnancy rates, abortion rates among these sexually experienced teenaged girls declined during the 1980s. Between 1980 and 1985, birth rates among teenaged girls aged 15 to 19 years declined by 4%, but they increased by 18% during the latter half of the decade, totaling 59.9 births per 1000 in 1990. Among these sexually experienced teenagers, birth rates also declined between 1980 and 1985 and then increased over the next 5 years. In 1990, pregnancies and abortions among girls younger than 15 years accounted for only 3% of all adolescent pregnancies and abortions. However, the number of births among these younger adolescents increased by 15% over the decade. In that age group, trends in pregnancy, abortion and birth rates over the decade were similar to those for older teens. However, during the late 1980s, the abortion rate declined and the pregnancy rate remained stable, resulting in a 26% increase in the birth rate.

CONCLUSIONS

Despite efforts to reduce adolescent pregnancy in the United States, pregnancy and birth rates for that group continue to be the highest among developed countries. Considering that 95% of adolescent pregnancies are unintended, increased efforts to prevent these pregnancies are warranted.

Previous cesarean delivery and the risk of ectopic pregnancy

OBJECTIVE

To determine whether previous cesarean delivery is an independent risk factor for ectopic pregnancy.

METHODS

We analyzed data collected between October 1988 and August 1990 from a case-control study of ectopic pregnancy among parous, black, non-Hispanic women, 18-44 years old, at a major metropolitan hospital in Georgia. Cases were 138 women with confirmed ectopic pregnancy; controls were 842 women either seeking abortion or delivering an infant. Unconditional logistic regression was used to estimate the relative risk while controlling for the effects of potential confounders selected a priori.

RESULTS

Adjusted for age, parity, marital status, history of pelvic inflammatory disease, infertility, douching, and smoking, the odds ratio was 0.6 (95% confidence interval 0.4-1.1), indicating no significant association.

CONCLUSION

We found no evidence of an increased risk of ectopic pregnancy related to previous cesarean delivery.

Hysterectomy in the United States, 1988-1990

OBJECTIVE

To describe patient characteristics and diagnoses associated with hysterectomy in the United States from 1988-1990 using data from the National Hospital Discharge Survey.

METHODS

We analyzed data from the National Hospital Discharge Survey, an annual probability sample of discharges from nonfederal, short-stay hospitals in the United States. A population-based sample of all women aged 15 years or older in the United States civilian population who had a hysterectomy during 1988-1990 was examined to characterize factors associated with hysterectomy: patients' age and race, diagnoses, surgical approach, and oophorectomy.

RESULTS

Approximately 1.7 million women had a hysterectomy during 1988-1990. The highest rates--100.5 hysterectomies per 10,000 women--were for women aged 30-54 years. Total rates of hysterectomy for black women were similar to those for white women (61.7 and 56.5 per 10,000 women, respectively); uterine leiomyoma ("fibroid tumor") was reported as the primary diagnosis for 61% of black women and 29% of white women. Abdominal surgery was used for 75% of all hysterectomies. Concomitant bilateral oophorectomy was done for 37% of the women under 45 years old and 68% of the women 45 years or older.

CONCLUSIONS

Two-thirds of all hysterectomies for noncancerous conditions were performed for uterine leiomyoma or endometriosis--conditions that are most common before the age of menopause. Future assessments of the appropriateness of hysterectomy will require better understanding of these disorders. Continued monitoring of hysterectomy rates is critical to understanding the appropriate use of hysterectomy, alternative therapies for uterine disorders, and future trends in women's health care.

Surveillance for pregnancy and birth rates among teenagers, by state--United States, 1980 and 1990

PROBLEM/CONDITION

In the United States in 1990, there were an estimated 1 million pregnancies and 521,826 births among women ages 15-19 years. Rates of teenage pregnancy and birth rates by state in 1990 exceeded those in most developed countries. An estimated 95% of teenage pregnancies are unintended (i.e., they occur sooner than desired or are not wanted at any time).

REPORTING PERIOD COVERED

This report summarizes and reviews surveillance data for pregnancies, abortions, and births among women ages 15-19, 15-17, and 18-19 years reported by CDC for 1980 and 1990.

DESCRIPTION OF SYSTEM

Data for births and abortions were reported to state health departments and other health agencies and sent to CDC. The data from each state included the total number of births and abortions by age and race/ethnicity.

RESULTS

Data in this report indicate that pregnancy rates by state among U.S. teenagers ages 15-19 years have changed little since 1980. Moreover, many states have reported increases in birth rates that are probably related to concurrent decreases in abortion rates. Pregnancy rates range from 25 to 75 per 1,000 for 15- to 17-year-olds and from 92 to 165 per 1,000 for 18- to 19-year-olds.

INTERPRETATION

States with low rates of teenage pregnancy or birth may have developed and used prevention strategies directed at the needs of both younger and older teenagers; these programs may serve as models for other states where birth rates have remained high or have increased since 1980.

ACTIONS TAKEN

CDC will continue to conduct surveillance of and analyze data for pregnancies, abortions, and births among teenagers to monitor progress toward national goals and to assist in targeting program efforts for reducing teenage pregnancy.

Overview of the National Infant Mortality Surveillance (NIMS) project

A slowdown in the decline of infant mortality in the United States and a continuing high risk of death among black infants (twice that of white infants) prompted a consortium of Public Health Service agencies, in collaboration with all states, to develop a national data base of linked birth and infant death certificates for the 1980 birth cohort. This project, referred to as National Infant Mortality Surveillance (NIMS), provides neonatal, postneonatal, and infant mortality risks for blacks, whites, and all races in 12 categories of birthweights. Tabulations were requested for infants born in single and multiple deliveries. For single-delivery births, tabulations included birthweight, age at death, race of infant, and each of these characteristics: infant's live-birth order, sex, gestation, type of delivery, and cause of death; and mother's age, education, prenatal care history, and number of prior fetal losses at greater than or equal to 20 weeks' gestation. An estimated 95% of eligible infant deaths were included in the NIMS tabulations. Analyses have focused on various components of infant mortality, including birthweight distribution of live births, neonatal mortality, and postneonatal mortality. The most important predictor for infant survival is birthweight; survival increases exponentially as birthweight increases to its optimal level. The nearly twofold higher risk of infant mortality among blacks than among whites was related to a higher prevalence of low birthweights, to higher mortality risks in the neonatal period for infants with birthweights of greater than or equal to 3,000 g, and to higher mortality during the postneonatal period for all infants, regardless of birthweight. Moreover, the black-white gap persisted for infants with birthweight of greater than or equal to 2,500 g, regardless of other infant or maternal risk factors.

Older maternal age and infant mortality in the United States

We used data from the National Infant Mortality Surveillance project to examine the effect of older maternal age on infant mortality for the 1980 United States birth cohort. The 1,579,854 births and 14,591 deaths of singletons who were black or white and whose mothers were 25-49 years of age were included. Direct standardization was used to calculate birth-weight-adjusted relative risks of neonatal and postneonatal mortality, using the birth weights of infants with maternal age 25-29 as the standard. We found that the risk of infant mortality was nearly equal for infants born to mothers 25-29 and 30-34 years of age; infants born to mothers 35-39 years of age were at a slightly elevated (18% higher) risk, and those born to mothers 40-49 years of age were at a much more elevated (69% higher) risk. Among whites, the higher neonatal mortality associated with a maternal age of 35-39 was mostly due to an increased prevalence of low birth weight; among blacks, it was due to higher birth-weight-specific risks. Neither white nor black postneonatal mortality risks were much elevated until a maternal age of 40-49, and this last elevation was mostly due to higher birth-weight-specific risks. These findings suggest that infertility and fetal mortality aside, and considering only the effect on infant mortality, it is relatively safe for women to postpone childbearing into their middle, and perhaps late, thirties.

Birthweight-specific infant mortality for native Americans compared with whites, six states, 1980

We used data from the National Infant Mortality Surveillance (NIMS) project to compare birthweights and birthweight-specific mortality risks among Native American and White infants. Because race categories in NIMS were limited to White, Black, and all, we studied six states in which greater than 85 per cent of newborns who were neither White nor Black were Native American. In these states, the infant mortality risk (IMR) among Native Americans was 15.3 deaths per 1,000 live births compared with 8.7 deaths among Whites, relative risk (RR) = 1.8 (95% CI = 1.5-2.0). The percentage of Native American infants with less than 2,500 g birthweights was 5.8 per cent versus 5.0 per cent for White infants. Birthweight-specific neonatal mortality risks were similar for the two race groups, but birthweight-specific postneonatal mortality risks (PNMRs) were more than three times as high among Native Americans compared with Whites for infants of greater than or equal to 2,500 g birthweight. PNMRs were elevated for most causes of death and for all categories for maternal age, educational attainment, trimester prenatal care began, and number of previous live births. Leading causes of postneonatal death among Native Americans of greater than or equal to 2,500 g birthweight were sudden infant death syndrome and infections.

Pregnancy and birth rates among sexually experienced US teenagers--1974, 1980, and 1983

We examined pregnancy rates and birth rates among United States teenagers aged 15 to 19 years in 1974, 1980, and 1983. Pregnancy rate refers to live births plus induced abortions per 1000 women; birth rate refers to live births per 1000 women. We present these rates for all teens aged 15 to 19 years and for teens aged 15 to 19 years who were sexually experienced. Data sources included National Center for Health Statistics birth records, Centers for Disease Control abortion surveillance reports, and Bureau of the Census population estimates. Sexual experience estimates came from national surveys of adolescent sexual behavior. Between 1974 and 1980, the pregnancy rate among all teens increased; the pregnancy rate among sexually experienced teens declined. From 1980 to 1983, the pregnancy rate declined among all teens and among sexually experienced teens. Birth rates among US teenagers (all teens and sexually experienced teens) declined between 1974 and 1983. Whereas the decline in the birth rate from 1974 to 1980 was primarily due to increased use of abortion, the decline from 1980 to 1983 related to the decrease in teenage pregnancies.

Differences in neonatal and postneonatal mortality by race, birth weight, and gestational age

In recent decades, neonatal and postneonatal mortality rates have declined overall in the United States. Yet, the mortality rates for black infants continue to be approximately twice those for white infants. With the use of data from 45 of the 53 vital statistics reporting areas that participated in the 1980 National Infant Mortality Surveillance project, we extended previous State analyses to describe differences, nationally, in neonatal and postneonatal mortality risks for black and white infants according to gestational age and birth weight. After restricting our analysis to single-delivery infants with known and plausible combinations of gestational age of 26 or more weeks and birth weights of 500 grams (g) or more, the neonatal mortality risk (NMR)--that is, the number of deaths to infants less than 28 days of life per 1,000 live births--for black infants was 1.6 times higher than the NMR for whites. This difference was largely explained by two findings: First, although the NMR was lower for black than for white infants with gestational ages of less than 38 weeks and birth weights less than 3,000 g, that advantage was heavily outweighed by the higher percentage of such births among blacks, accounting for roughly two-thirds of the overall difference in NMR between blacks and whites. Second, most of the remaining difference in NMR was accounted for by higher NMRs among black infants with gestational ages of 38 or more weeks and birth weights of 3,000 g or more. A comparison of the lowest mortality risk for any combination of birth weight and gestational age showed that the black NMR was 1.89 times higher than the white NMR. The postneonatal mortality risk (PNMR)--PNMR equals the number of deaths to infants 28 days to less than 1 year of life per 1,000 neonatal survivors--for black infants was 2.09 times the PNMR for white infants. Black infants had higher PNMRs than white infants for nearly all combinations of birth weight and gestational age. Higher PNMRs among infants with gestational ages of 38 or more weeks and birth weights of 2,500 g or more accounted for 43 percent of the difference in PNMR between black infants and white infants. Eliminating the U.S. black-white infant mortality disparity will require not only reducing the higher frequency of prematurity and low birth weight among black infants, but also improving the survival during both the neonatal and postneonatal periods of term black infants with normal birth weights.

Variation in state-specific infant mortality risks

Data from the National Infant Mortality Surveillance project were used to examine the State-specific variations in infant, neonatal, and postneonatal mortality and to examine some of the factors affecting the risks of death. The infant mortality risk, defined as the risk of death before 1 year of age to an infant born in the 1980 birth cohort, in the highest risk State was nearly three times that in the lowest risk State. Mortality risk ratios of two or greater were found when comparing high and low States for overall black infant mortality risks, overall neonatal mortality, neonatal mortality risks for black and white infants examined separately, neonatal mortality risks for low birth weight infants regardless of race, and overall postneonatal mortality and postneonatal mortality for white infants. The lowest State-specific black mortality risks were higher than the highest white risks for overall infant mortality and neonatal mortality. The differences between State extremes in mortality risks are greater than the differences between the United States and the Scandinavian countries with the lowest infant mortality.

Analysis of unlinked infant death certificates from the NIMS project

The National Infant Mortality Surveillance (NIMS) project used linked birth and infant death certificates to calculate birth weight-specific infant mortality risks for the 1980 U.S. birth cohort. Record linkage depends on complete registration of vital events, interstate exchange of vital records, accurate information on certificates, and a comprehensive linkage system. States reported 2,604 unlinked infant death certificates for 1980, ranging from 0 to 397 per State. Age at death for these infants ranged from 1 minute to 11 months. More than 41 percent of the unlinked death certificates were for postneonates, compared with 32.5 percent found in the cohort's total infant death experience. Only 38.2 percent of the unlinked infant death certificates showed strictly intrastate events (birth and death occurrence, and residence at death all in one State), compared with 92.9 percent in the cohort's total infant death experience. Estimates of the percentage successfully linked by State ranged from 86.0 to 100.0. After adjusting for the certainly unlinked infant death certificates, nine States' infant mortality risks increased by more than 0.2 per 1,000 live births. Improvements are needed both within and between States to ensure more complete birth and infant death certificate linkage.

Birth weight-specific causes of infant mortality, United States, 1980

To describe underlying causes of infant death by birth weight, we used data from the 1980 National Infant Mortality Surveillance project and aggregated International Classification of Diseases codes into seven categories: perinatal conditions, infections, congenital anomalies, injuries, sudden infant death syndrome (SIDS), other known causes, and nonspecific or unknown causes. Compared with heavier infants, infants with birth weights of 500-2,499 grams (g) are at increased risk of both neonatal and postneonatal death for virtually all causes. Sixty-two percent of neonatal deaths (under 28 days of life) were attributed to "conditions arising in the perinatal period," as defined using codes from the International Classification of Diseases. Prematurity-low birth weight and respiratory distress syndrome (RDS) were the leading causes of such deaths among infants with birth weights of 500-2,499 g, while birth trauma-hypoxia-asphyxia and other perinatal respiratory conditions were the leading causes among heavier infants. For all birth weight groups, congenital anomalies were the second leading cause, representing 27 percent of neonatal deaths. Although perinatal conditions caused nearly one-third of postneonatal deaths (28 days to under 1 year of life) among infants with birth weights of 500-1,499 g, for the other birth weight groups these conditions were much less important; predominant causes of postneonatal death were sudden infant death syndrome (SIDS), congenital anomalies, infections, and injuries. Black infants had a roughly twofold higher risk of neonatal and postneonatal death than did white infants for all causes except congenital anomalies, which occurred with almost equal frequency in blacks and whites. However, for infants with birth weights of 500-2,499 g, blacks had lower risks of neonatal death from RDS and congenital anomalies. Between 1960 (the latest year for which national birth weight-specific mortality statistics had been available) and 1980, SIDS emerged as a major diagnostic rubric. Otherwise, except for infections and congenital anomalies among infants with birth weights of 500-1,499 g, all causes of death declined in frequency among all birth weight groups.

Regional differences in birth weight-specific infant mortality, United States, 1980

To describe regional differences in birth weight-specific infant mortality in the United States, we used data from the National Infant Mortality Surveillance project. The infant mortality risk (IMR) for the nation was 11.0 deaths per 1,000 live births. The risk (with 95 percent confidence intervals [CI]) for the four U.S. Census regions were West 9.9 (9.7 to 10.1), Northeast 10.4 (10.1 to 10.6), North Central 10.8 (10.6 to 11.0), and South 12.1 (11.9 to 12.3). In all regions, the IMR for blacks was approximately twice that of whites. Seventy-two percent of the higher IMR in the South was due to a higher proportion of black births compared with the remainder of the nation, reflecting the higher mortality rates suffered by black infants, and 28 percent to higher mortality among southern whites. The IMR for whites in the South was significantly higher than in the remainder of the nation: 9.8 versus 9.1 (relative risk = 1.09, CI = 1.06 to 1.11). Thirty-six percent of this excess in IMR was due to a higher frequency of low birth weight (less than 2,500 grams), 18 percent was due to higher IMR in infants with birth weight less than 2,500 grams, and 46 percent due to higher IMR in infants with birth weights of 2,500 g or more. Black infants born in the West had a lower risk of death than black infants in the other regions. When compared with the Northeast and South, 36 percent of the lower risk in the West among black infants was due to a lower frequency of low birth weight, 38 percent due to lower IMR in infants w'ith birth weight less than 2,500 g, and 26 percent to lower IMR in infants with birth weight of 2,500 g or more.

Experiences with linked birth and infant death certificates from the NIMS project

The National Infant Mortality Surveillance (NIMS) project aggregated data provided by 53 vital statistics reporting areas--50 States, New York City, the District of Columbia, and Puerto Rico (subsequently called States)--from their files of linked birth and death certificates and compared individual States' total infant mortality experiences for the 1980 birth cohort by age at death, race, birth weight, and plurality. Therefore, it was essential to achieve maximum uniformity among the separate data sets and to specify when this uniformity could not be obtained. In working with these multiple sources, we identified five key issues that relate to data from linked birth and death certificates: Variations in definitions of variables are often embedded in data that have been gathered from several independent sources. (For NIMS, the sources were 53 reporting areas and the National Center for Health Statistics.) Variations in States' linking procedures--these are based on an individual State's primary purpose for linking the data--affect the completeness and comparability of the 1980 resident birth cohorts used for NIMS. Variations in the recording of some pregnancy outcomes as fetal deaths or live births are known to be a problem in vital statistics data that particularly affects data for events among infants weighing less than 500 g at birth. Ambiguities occur frequently in unknowns or zero values. For NIMS this effect was most pronounced for the pregnancy history variables. Examination of the values reported for unknown or zero categories helps in uncovering problems with and improving quality of data. (e) Analysis from a new perspective may reveal unexpected data problems. These problems tend to surface only during a reexamination of underlying data that is prompted by unusual findings.Continued alertness to these issues may improve further the quality of data in files of linked birth and death certificates and assure the integrity of analysis based on these data.

Birth weight-specific infant mortality, United States, 1960 and 1980

National statistics on the risk of infant mortality by birth weight were collected most recently in 1980 and 1960. (Infant mortality risk is the number of deaths of infants under 1 year of age per 1,000 live births.) In this 20-year period, the infant mortality risk (IMR) for single-delivery infants declined 53 percent, from 23.3 deaths per 1,000 live births to 11.0; 91 percent of this decline was due to lower IMRs within birth weight categories, and 9 percent was due to reduced frequency of low birth weight. The greatest reduction in neonatal mortality (under 28 days)--73 percent--occurred among infants of 1,500-1,999 grams (g) birth weight, whereas the greatest reductions in postneonatal mortality (28 days to under 1 year)--51 percent to 54 percent--occurred among infants of 3,500 g or more birth weight. Trends in IMR for black and white infants were similar, and the twofold gap between the races in IMR persisted from 1960 to 1980. For whites, reductions in the frequency of low birth weights contributed to the decline in the IMR. For blacks, the percentage of infants with birth weights of less than 1,500 g increased, and the total reduction in the IMR was attributable to lower birth weight-specific mortality risks. In some regions of the United States, failure to observe an increase in birth weight for blacks may be a reporting artifact, reflecting improved reporting of births of very small black infants in 1980. Examination of changes in perinatal mortality risks (from 20 weeks gestation to less than 28 days of life) did not suggest that infant mortality trends were substantially affected by changes in the distinction between fetal and neonatal deaths over the 20-year period. Reducing the number of low birth weight infants remains the greatest potential for future reductions in infant mortality.

Overview of the National Infant Mortality Surveillance (NIMS) project--design, methods, results

The recent slowdown in the decline of infant mortality in the United States and the continued high risk of death among black infants (twice that of white infants) prompted a consortium of Public Health Service agencies to collaborate with all States in the development of a national data base from linked birth and infant death certificates. This National Infant Mortality Surveillance (NIMS) project for the 1980 U.S. birth cohort provides neonatal, postneonatal, and infant mortality risks for blacks, whites, and all races in 12 categories of birth weights. (Note: Neonatal mortality risk = number of deaths to infants less than 28 days of life per 1,000 live births; postneonatal mortality risk = number of deaths to infants 28 days to less than 1 year of life per 1,000 neonatal survivors; and infant mortality risk = number of deaths to infants less than 1 year of life per 1,000 live births.) Separate tabulations were requested for infants born in single and multiple deliveries. For single-delivery births, tabulations included birth weight, age at death, race of infant, and each of these characteristics: infant's live-birth order, sex, gestation, type of delivery, and cause of death; and mother's age, education, prenatal care history, and number of prior fetal losses at 20 weeks' or more gestation. An estimated 95 percent of eligible deaths were included in the NIMS tabulations. The analyses focus on three components of infant mortality: birth weight distribution of live births, neonatal mortality, and postneonatal mortality. The most important predictor for infant survival was birth weight, with an exponential improvement in survival by increasing birth weight to its optimum level. The nearly twofold higher risk of infant mortality among blacks was related to a higher prevalence of low birth weights and to higher mortality risks in the neonatal period for infants weighing 3,000 grams or more, and in the postneonatal period for all infants, regardless of birth weight. Regardless of other infant or maternal risk factors, the black-white gap persisted for infants weighing 2,500 grams or more.

Young maternal age and infant mortality: the role of low birth weight

In 1980, there were 562,330 babies born in the United States to teenage mothers (19 years of age or younger). The offspring of teenage mothers have long been known to be at increased risk of infant mortality, largely because of their high prevalence of low birth weight (less than 2,500 grams). We used data from the National Infant Mortality Surveillance (NIMS) project to examine the effect of young maternal age and low birth weight on infant mortality among infants born in 1980 to U.S. residents. This analysis was restricted to single-delivery babies who were either black or white, who were born to mothers ages 10-29 years, and who were born in one of 48 States or the District of Columbia. Included were 2,527,813 births and 28,499 deaths (data from Maine and Texas were excluded for technical reasons). Direct standardization was used to calculate the relative risks, adjusted for birth weight, of neonatal mortality (less than 28 days of life) and postneonatal mortality (28 days to less than 1 year of life) by race and maternal age. There was a strong association between young maternal age and high infant mortality and between young maternal age and a high prevalence of low birth weight. Neonatal mortality declined steadily with increasing maternal age. After adjusting for birth weight, the race-specific relative risks for babies born to mothers less than 16 years of age were still elevated from 11 to 40 percent, compared with babies born to mothers 25-29 years of age. Otherwise, all the relative risks were nearly equal to 1. By contrast, most of the association between young maternal age and postneonatal mortality persisted after birth weight adjustment in all maternal age groups.These results suggest that the prevention of neonatal mortality and, to a lesser extent, postneonatal mortality among babies born to teenagers depends on preventing low birth weight. The prevention of postneonatal mortality may depend more on other factors, such as assisting teenagers with better parenting. Finally, although there maybe few biological reasons to postpone childbearing,teenage childbearing continues to place the mother and her baby at a social disadvantage.

Birth weight-specific infant mortality due to congenital anomalies, 1960 and 1980

The impact of mortality due to congenital anomalies in single-delivery births was compared in 1960 and 1980 birth cohorts; data were used from the 1960 National Center for Health Statistics national linkage of birth and death certificates and the 1980 National Infant Mortality Surveillance project. In 1960 there were 14,714 deaths due to congenital anomalies, compared with 8,674 in 1980, a 41 percent reduction. The infant mortality risk (IMR) due to congenital anomalies fell 31 percent. This is in contrast with the observed 54 percent decline in IMR due to all causes. This reduction in mortality due to congenital anomalies occurred for both whites and blacks in the postneonatal period and for whites only in the neonatal period. Changes ranged from a 1.8 percent increase for the black neonatal mortality risk to a 46.6 percent decrease for the white postneonatal mortality risk. In spite of these relative reductions, the absolute percentage of all infant deaths due to congenital anomalies had increased from 15.8 percent in 1960 to 24.1 percent in 1980. Two categories, cardiovascular and central nervous system anomalies, accounted for 72 percent of infant deaths due to congenital anomalies in 1960 and for 59 percent in 1980; cardiovascular anomalies accounted for 48 percent of all deaths due to congenital anomalies in 1960 and 40 percent in 1980. Infant mortality risks in the United States showed a 2:1 black to white ratio in both 1960 and 1980. However, for infant mortality due to congenital anomalies, the black and white mortality risks were approximately equal in both 1960 and 1980. For infants with birth weights of 500-2,499 g, the risk of neonatal mortality for blacks was less than half the risk for whites.

Previous experience of induced abortion as a risk factor for fetal death and preterm delivery

As part of a community-based study in Korea to evaluate the effects of previous induced abortion on length of gestation and pregnancy outcome of subsequent pregnancies, we analyzed data obtained from January 1979 to December 1981 on pregnancies reported to family health workers in Kang Hwa Island, Korea. The preterm, live-birth rates were not significantly associated with previous induced abortion. Overall, the life table-estimated fetal death rate for women enrolled at the eighth or earlier weeks of gestation was 13.7%, 10.2% for women with no previous induced abortion and 28.9% for women with previous induced abortion. The relative risk for fetal death for women who had undergone a previous abortion was 2.8; relative risk for parous women compared to nulliparous women was 3.4. After controlling for parity, previous induced abortion was not a significant variable for fetal death rate.

Sterilization-associated deaths: a global survey

Except for data from several geographically limited studies, little is known globally about the number and causes of death associated with surgical sterilization. To identify clinical characteristics and problems leading to deaths related to the procedures, the International Planned Parenthood Federation ( IPPF ) and the Centers for Disease Control (CDC) in the United States collaborated in a global mail survey of 4642 physicians. Usable responses were received from 1298 physicians (28%) in 80 countries. Fifty-five sterilization-associated deaths which occurred from January 1, 1980 to June 30, 1982 were reported. The most frequently reported causes of death were infection, anesthetic complications, and hemorrhage. There were some regional differences in the relative frequencies of these causes. Most cases did not involve surgical accident. The characteristics most frequently associated with the reported fatal procedures were: interval sterilizations, minilaparotomy incision, tubal ligation and general anesthesia. Most deaths were attributable to the surgical sterilization procedure.

A comparison of primary and secondary homicides in the United States

In 1979, over 20,000 people in the United States were victims of homicide, but public health agencies have not yet defined their role in its prevention. Role definition might begin with differentiating various forms of homicide, so the authors used data on all homicides reported by law enforcement agencies for 1976-1979 to determine whether homicides that did not occur during the perpetration of another crime (primary homicides) differ from those that occurred during the perpetration of another crime (secondary homicides). Primary and secondary homicide rates were highest in the South and West, respectively. The relative risk for Standard Metropolitan Statistical Areas (SMSAs) compared with non-SMSAs was 2.4 for secondary homicide but only 1.3 for primary homicide. It was found that 17% of primary homicides and 3% of secondary homicides had a female offender. Primary homicides were more frequently intersexual and intraracial than were secondary homicides. Victim and offender ages were similar to one another in primary homicides and dissimilar in secondary ones. Over 75% of primary homicides involved family members or acquaintances, compared to only 24% of secondary homicides. The authors conclude that primary and secondary homicides are epidemiologically dissimilar, and they suggest that public health concern should focus on primary homicide. Prevention and intervention measures should concentrate on discussed target populations. Techniques might include stress reduction and conflict avoidance.

Agreement between women's histories of oral contraceptive use and physician records

The histories of oral contraceptive (OC) use provided by women participating in a study of hepatocellular adenoma (HCA) were compared with records obtained from their physicians. In the HCA study two memory aids were used to assist women in their recall: a calendar of significant events during a woman's lifetime to which she might relate her use of OCs and a book of colour photographs of the 90 OC preparations available up to the time of the study. Using the number of months of a woman's history which could be checked against physician records (mean for all women of 33 months) as the denominator, the highest proportion of concordance was for month-specific duration of OC use (90%) with lower agreement for duration and brand (62%) and duration, brand, and dose (54%). Agreement was better for cases than for controls.

Complications of interval laparoscopic tubal sterilization

In 1978, the Centers for Disease Control initiated a multicenter prospective study to assess the safety of the various female sterilizing operations and the ways in which they could be made safer. During the first 31 months, 3500 women who underwent interval laparoscopic tubal sterilization by electrocoagulation or Silastic banding without other concurrent operations were enrolled in the study. When a standard definition of complications was used, the overall rate of an intraoperative or postoperative complication was 1.7 per 100 women. Several patients factors increased the risk of complications twofold or more: diabetes mellitus, previous abdominal or pelvic surgery, lung disease, a history of pelvic inflammatory disease, and obesity. There was a fivefold difference in complication rates between procedures performed under general anesthesia and those done under local anesthesia.

Complications of abdominal and vaginal hysterectomy among women of reproductive age in the United States. The Collaborative Review of Sterilization

Although hysterectomy was the most frequently performed major surgical procedure among women of reproductive age during the past decade, few recent studies have been conducted to determine the risk of complications. We examined data from the Collaborative Review of Sterilization, a prospective, multicenter, observational study coordinated by the Centers for Disease Control, to assess the comparative risks of complications among women undergoing hysterectomy by the abdominal and vaginal approaches. Between September, 1978, and August, 1981, 1,851 women from nine institutions were included in the study. Women who underwent vaginal hysterectomy experienced significantly fewer complications than women who had undergone abdominal hysterectomy. The difference was probably attributable to the prevalence and efficacy of prophylactic antibiotic use among the former group. Vaginal hysterectomy was associated with more unintended major surgical procedures but less febrile morbidity, bleeding requiring transfusion, hospitalization, and convalescence than abdominal hysterectomy. Vaginal hysterectomy with prophylactic antibiotics should be strongly considered for those women of reproductive age for whom either surgical approach is clinically appropriate.

Oral contraceptive during lactation: a global survey of physician practice

The use of combined estrogen-progestogen oral contraceptives (EP-OC) by lactating women has been associated with suppression of lactation. To determine the extent to which physicians prescribe combined EP-OC for lactating women, the International Planned Parenthood Federation (IPPF) and the United States Centers for Disease Control (CDC) collaborated in a global mail survey of 3697 physicians affiliated with Family Planning Associations (FPA) in 72 countries. Usable responses were received from 831 physicians (22%) in 65 countries. The percent of clinicians who provide EP-OC to lactating women was higher in developing regions (63% or more) than in developed regions (40% or less). Patient preference was rated important more often than any other factor in the decision to prescribe EP-OC for lactating women. The percentage of clinicians who reported complaints of decreased milk production from women using EP-OC was higher (32% or more) in developing regions where breast milk is often essential to infant nutrition.

Epidemiology of hepatocellular adenoma. The role of oral contraceptive use

A case-control study of hepatocellular adenoma (HCA), a serious though nonmalignant liver tumor, was conducted by the Center for Disease Control and the Armed Forces Institute of Pathology (AFIP). Interviews with 79 women with HCA and with 220 age- and neighborhood-matched controls were completed. Limited information was obtained on nine additional patients who had died. Women with HCA and hemorrhage have a greater risk of morbidity and death than those with other symptoms. Increasing duration of OC use increases the risk of HCA. Use of OCs with high hormonal potency and age over 30 years may further increase a woman's risk of HCA. Long-term users of OCs have an estimated annual incidence of HCA of 3 to 4 per 100,000.

Epidemiology of hepatocellular adenoma. The role of oral contraceptive use

A case-control study of hepatocellular adenoma (HCA), a serious though nonmalignant liver tumor, was conducted by the Center for Disease Control and the Armed Forces Institute of Pathology (AFIP). Interviews with 79 women with HCA and with 220 age- and neighborhood-matched controls were completed. Limited information was obtained on nine additional patients who had died. Women with HCA and hemorrhage have a greater risk of morbidity and death than those with other symptoms. Increasing duration of OC use increases the risk of HCA. Use of OCs with high hormonal potency and age over 30 years may further increase a woman's risk of HCA. Long-term users of OCs have an estimated annual incidence of HCA of 3 to 4 per 100,000.

Fertility in psychiatric outpatients

The fertility rates of 223 female schizophrenic outpatients and 479 female nonschizophrenic outpatients were compared to a probability sample of 300 women residing in the same geographic area, metropolitan Atlanta, and from the same social strata as the patients. Age- and race-adjusted comparisons showed that the mean number of children per woman and levels of unwanted and unplanned fertility did not differ in the different diagnostic groups. Furthermore, the rates were not lower for the psychiatric patients than for the general population. In order to reduce an important source of psychiatric morbidity, those in the mental health professions need to pay more attention to the family planning desires of their patients.

The association between oral contraception and hepatocellular adenoma--a preliminary report

Women with long-term use of oral contraception (OC) are at increased risk of developing a serious, though nonmalignant, liver tumor--hepatocellular ademona (HCA)--according to a case-control study conducted by the Center for Disease Control (CDC) in collaboration with the Armed Forces Institute of Pathology (AFIP). The tumor is sometimes fatal, deaths usually being due to sudden rupture and hemorrhage. This study suggests that, in addition to long-term OC use, a women's age and the hormonal potency of the OC she uses affect her changes of developing HCA. Women 27 years old and older who have used OC with high hormonal potency for 7 or more years are at the greatest risk.