Differences in trends of postneonatal mortality by birthweight in upstate New York, 1968-1979

Postneonatal mortality in Alabama: why no progress in the 90s?

PURPOSE

To examine the factors associated with postneonatal mortality.

METHODS

Logistic regression was used to examine the effects of various variables on postneonatal mortality in Alabama.

RESULTS

The most important predictor of postneonatal mortality was birth weight. Social and economic variables were also important in explaining postneonatal mortality.

CONCLUSIONS

Reductions in postneonatal mortality may require closer case management of low birth weight neonatal survivors. Survival of these infants creates a cohort at risk of postneonatal mortality. Many of these low birth weight infants are born into an environment where their mothers' parenting potential is compromised by youth and poverty. This may be responsible for the failure to reduce postneonatal mortality and explain its increasing proportion of infant deaths; deaths may be being postponed from the neonatal to the postneonatal period.

Risk status at discharge and cause of death for postneonatal infant deaths: a total population study

OBJECTIVES

To obtain population-based, clinical information regarding potentially modifiable factors contributing to death during the postneonatal period (28 to 364 days), we examined all postneonatal infant deaths in four areas of the United States to determine: (1) the cause of death from clinical and autopsy data rather than vital statistics, (2) whether death occurred during initial hospitalization or after discharge, and (3) the portion of postneonatal mortality attributable to infants who left the hospital with identified high-risk medical conditions.

DESIGN AND SETTING

Retrospective medical record review of all postneonatal infant deaths with birth weights greater than 500 g (total N = 386) born to mothers residing in: (1) the city of Boston (1984 and 1985, N = 55), (2) the city of St Louis and contiguous areas (1985 and 1986, N = 123), (3) San Diego County (1985, N = 112), and (4) the state of Maine (1984 and 1985, N = 96). Deaths were identified using linked birth and death vital statistics, and medical record audits of infants' and mothers' charts were performed. Causes of death were obtained from medical record review in conjunction with autopsy if performed (72%, N = 278), medical record alone (17%, N = 67), or vital statistics if no other source was available (11%, N = 41). The medical conditions at the time of discharge for each infant were reviewed and, if judged to confer an increased risk of morbidity or mortality, were classified as high risk.

RESULTS

The causes of death were sudden infant death syndrome (47%, N = 181), congenital conditions (20%, N = 77), prematurity-related conditions (11%, N = 43), infections (9%, N = 34), external causes (including injuries, drownings, ingestions, and burns) (7%, N = 25), and other (6%, N = 23). In 24% of congenital and 25% to 44% of prematurity-related deaths, infection was the acute or associated cause of death. Infants born to black mothers were more likely than those born to white mothers to die during the postneonatal period of all major causes of death (7.3 per 1000 vs 3.0 per 1000). Overall, 18% (N = 68) of deaths occurred to infants who never left the hospital; 79% (N = 305) of the infants were discharged before death; and discharge status was unknown in 3% (N = 13). Eighty-one percent of all infants with prematurity-related postneonatal deaths were never discharged, and of the total infants who were initially discharged, only 1% (N = 4) subsequently died of prematurity-related causes. Of all postneonatal deaths, only 16% (N = 62) left the hospital with identified high-risk medical conditions.

CONCLUSIONS

These findings suggest that the etiology of postneonatal mortality is heterogeneous, with significant complexity in attributing specific causes of death and making designations of "preventability." The vast majority of infants who died of prematurity-related postneonatal causes never left the hospital, and only a small percentage of all infants that left the hospital before death were identified as being at high medical risk. Therefore, strategies for further decreasing postneonatal mortality must link high-risk follow-up programs to more comprehensive strategies that address risk throughout pregnancy and early childhood.

Impact of increased neonatal survival on postneonatal mortality in the United States

Neonatal intensive care has increased neonatal survival, but has also led to postponement of some of the neonatal deaths to the postneonatal period, particularly in very low birthweight (< 1.5 kg) infants. Our report assesses the impact of the increased neonatal survival and the accompanying delayed deaths on the crude postneonatal mortality rate of the US, using the national livebirth cohort data of 1960, 1980, and 1986. With increased neonatal survival, very low birthweight infants comprised 0.68% of all neonatal survivors in 1986, compared with only 0.31% in 1960. However, postneonatal mortality was increased in infants with birthweights < 1.0 kg from 69 per 1000 neonatal survivors in 1960 to 116 per 1000 in 1986. All other birthweight groups (> 1.0 kg) showed significant reductions in their postneonatal mortality, although the 1.0-1.5 kg group showed the least improvement. Thus, in 1986, 12.1% of all postneonatal deaths were from the very low birthweight neonatal survivors, as compared with 2.7% in 1960. If there had been no improvement in neonatal survival of very low birthweight infants since 1960, the crude postneonatal mortality rate of the US would have been 5.5% and 7.9% less than the actual rates of 3.65 and 3.45 per 1000 neonatal survivors in 1980 and 1986, respectively. However, the impact of these delayed deaths in very low birthweight infants was far less than the increase in their neonatal survival: an additional 416 per 1000 very low birthweight infants survived to 1 year of age in 1986 as compared with 1960. Delayed deaths in the 1.5-2.5 kg birthweight group had a very small effect on postneonatal mortality and there was no such effect of delayed deaths in the > 2.5 kg birthweight group.

[The evolution of mortality in the first year of life in Spain (1975-1988)]

In recent years, the rate of decline in infant mortality and the proportional mortality by some causes of death in the first year of life have had important changes. The objectives of this study are to describe such changes, and to suggest hypotheses about their meaning. Infant, early neonatal, late neonatal and postneonatal mortality rates from 1975 to 1988 were calculated with information from the death register. Also, several indicators of the trends of those rates and proportional mortality by "certain conditions originating in the perinatal period" have been calculated. The reduction in infant mortality was due, mainly, to early neonatal mortality, which had an annual average decline of 4.6% during the study period. The proportional mortality and the mortality rate by perinatal conditions in the postneonatal period increased between 1975 and 1988. The first increased from 1.3% to 5.2%, and the second from 0.07 to 0.15 per 1000 live births. Hypotheses about the meaning of these results are suggested, and some actions are proposed in order to monitor and conduct research on mortality during the first year of life.

The impact of advances in medicine on the biometric analysis of infant mortality

Bourgeois-Pichat's biometric model was developed as a method to decompose infant mortality into endogenous and exogenous components. The model assumes that no endogenous deaths occur after the first month of life. This paper uses data for the United States to examine the hypothesis that recent advances in medicine extend endogenous mortality past the first month of life. The biometric model is found consistently to underestimate the endogenous infant mortality rate and to overestimate the exogenous infant mortality rate relative to cause of death analysis. Direct examination of the age distribution of infant mortality shows that the proportion of all infant mortality that occurs in the first month of life declined from 75.37 per cent in 1970 to 65.40 per cent in 1985, and that a significant and increasing proportion of the mortality occurring after the first month of life is due to endogenous causes. The development of new empirical models is suggested.

Preventing and postponing death: trends in Tennessee infant mortality

Infants born in Tennessee between 1984 and 1988 experienced reduced mortality compared with those born in the 5 years previous. For all birthweight singleton infants, the reduction from 10.2 to 8.4 deaths per 1000 live births represents an 18% decline in mortality. The most impressive gain made was for very low birthweight (less than 1500 g) infants in the neonatal period, where mortality was reduced 24%. However, for these infants there was nearly a sixfold increase in the postneonatal mortality associated with prematurity-related causes.

[The quality of the filling-in of death certificates of children below one year of age in the metropolitan area of Rio de Janeiro]

Within the scope of an investigation into infant mortality determinants in the metropolitan region of Rio de Janeiro during one-year period, the original death certificates of a sample of children were studied and compared with information provided on them by hospital case-histories and records. This was done with a view to assessing the quality of the filling in of certificates for the purpose of calling the attention of health officers to their use as documents furnishing data for the preparation and evaluation of health programmes and note simply as a legal requirement for burying. Only 52.3% of the basic causes given on the certificates were maintained after the examination of the case histories. Necropsy was carried out on only 42.8% of those neonatal deaths and 21.5% of post-neonatal deaths which took place outside the hospital. Other items that were evaluated included mother's age and education, time interval and complementary examination, birth weight and necropsy, all of which presented a degree of accuracy in their filling-in far below that required, thus evidencing the limitations of the official death statistics based on this information.

Causes of infant mortality in a multiethnic population

Causes of infant mortality and their change over time in five ethnic groups were investigated using linked infant death and live birth certificates from the State of Hawaii, 1968-1983. Over the study period, there were 3,324 deaths of which 31 percent were to Whites, 26 percent to Hawaiians, 17 percent to Asians, 15 percent to Filipinos and 10 percent to other ethnic groups. Significant changes in the proportion of deaths by cause occurred over the period. Perinatal causes remained the most frequent, but their relative contribution to annual infant deaths declined from 61 percent to 47 percent. The proportion of deaths from congenital anomalies increased from 19 percent to 30 percent, while the proportion of deaths from infectious diseases declined from 14 percent to 4 percent. There was a significant difference in the proportion of deaths by cause between ethnic groups in the early years of the study period. However, during the last four years 1980-1983, no significant difference between ethnic groups was observed.

Perinatal mortality in Northern Ireland: where are we now?

Perinatal mortality in Northern Ireland has been declining over the last 30 years, but the factors which may account for this fall have not been clearly delineated. Crude perinatal mortality figures yield very little insight into the problem, and meaningful management statistics are urgently required if service performance is to be reasonably assessed. This paper sets out the case for birth-weight standardisation and explores the utility of a broad diagnostic taxonomy of causes of death.

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.

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.

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.

The world economic crisis and the children: United States case study

This is a review of the United States experience with issues of child health and services as they relate to changes in economic trends. No existing data systems are entirely adequate for reporting on the current health status of children. An important consideration for the monitoring of children's health in the United States is the status of subgroups such as those who are disadvantaged for reasons of poverty, discrimination or geographic isolation. Ample evidence confirms that children living in poverty suffer adverse health consequences and that the proportion of children living in poverty in the United States has increased steadily since 1975 and dramatically since 1981. Most measures of health status and health risks for children show steady improvements throughout the 1970s. The exercise of public responsibility for financing and providing essential services and supports held constant or improved during this period, especially during the recession of 1974-75. The health status and risks for children since 1981 appear to be adversely affected which must be attributed to a combination of circumstances that include serious recession, increased poverty rates for households with children and diminished health benefits and social support services. These findings suggest that when either local or widespread economic reversals are anticipated, health services and social supports for children need to be expanded rather than contracted.