Trends in perinatal,neonatal and postneonatal mortality in Italy, 1955–84

Trends in stillbirth rates, perinatal, neonatal and postneonatal mortality in Italy over the perrod 1955–84 were analyzed. There was a 75% reduction (from 28.4 to 7.1/1000 births) in stillbirth rates, and a nearly 70% fall (from 46.2 to 14.5/1000 births) in overall perinatal mortality (from the 180th day of pregnancy to the first week of life). Further, mortality rates from the 8th to the 28th day of life dropped from 7.4 to 1.6/1000 livebirths, and mortality from the second month to the first year of life from 25.1 to 2.2/1000 livebirths. The fall in stillbirth rates was similarly evident across various indicators of maternal education and social class, and could only marginally be accounted for by changes in maternal age distribution. The causes of this large drop in perinatal, neonatal and postneonatal mortality are likely to be numerous and complex. In the absence of any comprehensive program of rationalization of obstetrical and neonatal care, a determinant role must have been played by a general improvement in economic and cultural conditions. However, the observation that decreased perinatal mortality was not due to a decline in the proportion of low birth weight indicates that improved perinatal care may have had an important role as well. Although the decrease in various measures of perinatal and postneonatal mortality in Italy was proportionally comparable with that registered in several other developed countries, Italian perinatal mortality rates (14.5/1000 births in 1984) still appear considerably higher than in other countries, and are clearly far from the optimal theoretical value.     

Birthweight and perinatal mortality among singletons and twins in north-eastern Tanzania

BACKGROUND: Low birthweights as well as high perinatal mortality rates are common in most African populations. Little is known, however, about how low birthweight corresponds with higher mortality rates within African populations. Twins are known to have lower birthweights and higher perinatal mortality rates than singletons. If lower birthweights represent higher perinatal risk per se, small twins within a population with generally lower birthweights should have critically increased risks. METHODS: In total, 15,255 births in a Tanzanian hospital during 1999-2006 were analysed to determine birthweight distribution and examine perinatal mortality rates (including stillbirths and neonatal deaths within 24 hours) by birthweight in twins and singletons. Referral births from outside the district where the hospital was situated were excluded from analysis. RESULTS: The mean birthweight for births within an estimated normal distribution was 3172 g, with a standard deviation of 462 g. The overall perinatal mortality rate was 43.9 per 1000 births (95% confidence interval: 40.7-47.2). Perinatal mortality rates among twins and singletons were 91.0 and 41.1 per 1000 babies respectively, corresponding to a relative risk of 2.2 (95% confidence interval: 1.7-2.8). The birthweight distribution for twins was shifted to lower birthweights. Twins had a generally lower birthweight and an excess of extremely small births as compared to singletons. The increased mortality rate for twins appeared to be independent of birthweight. CONCLUSIONS: The two-fold increased risk of perinatal death for twins was observed across the whole birthweight distribution, and very small twins appeared to have an excess perinatal risk that was almost similar to that of larger twins.     

Improvement in infant and perinatal mortality in the United States, 1965--1973: I. Priorities for intervention

Changes in United States infant and perinatal mortality in the period 1965--1973 were examined by race, age at death or length of gestation, and degree of urbanization. The decline of postneonatal mortality rates was greater than the declines of fetal and neonatal mortality rates. Other-than white infant and fetal mortality rates improved more than the white rates, except in the first day of life. Postneonatal mortality rates improved more in rural than in urban areas, while neonatal and perinatal mortality rates improved more in urban areas than in rural. These improvements in mortality rates have occurred at the same time as changes in medical techniques and the organization and availability of health services, improvements in economic conditions and standards of living, and changes in the demographic characteristics of the child-bearing population of the United States. Each of these changes was in a direction expected to have a favorable effect on infant and perinatal mortality. Nevertheless, the improvement of infant mortality rates has not changed the relative position of the United States in comparison with other countries. Programs to improve infant and perinatal mortality can use the data in this study to define high priority target groups using a method based on the size of the problem in the target group, the severity of the problem, and the amount and direction of change.     

Analysis of interrupted time series mortality trends: an example to evaluate regionalized perinatal care.

Interrupted time series designs are frequently employed to evaluate program impact. Analysis strategies to determine if shifts have occurred are not well known. The case where statistical fluctuations (errors) may be assumed independent is considered, and a segmented regression methodology presented. The method discussed ia applied to the assessment of changes in local and state perinatal postneonatal mortality to identify historical trends and will be used to evaluate the impact of the North Carolina Regionalized Perinatal Care Program when seven years of post-program mortality data become available. The perinatal program region is contrasted with a control region to provide a basis for interpretation of differences noted. Relevant segmented regression models provided good fits to the data and highlighted mortality trends over the last 30 years. Considerable racial differences in these trends were identified, particularly for postneonatal mortality. Segmented regression is considered relevant for the analysis of interrupted time series designs in other applications when errors can be taken to be independent. Thus, the methodology may be regarded as a general statistical tool for evaluation purposes.     

Avoidable mortality in Europe (1980-1997): a comparison of trends

STUDY OBJECTIVE: To analyse international variations of trends in "avoidable" mortality (1980-1997). DESIGN: A multilevel model was used to study trends in avoidable and "non-avoidable" mortality and trends by cause of death. SETTING: Fifteen countries of the European Union, the Czech Republic, and Hungary. PARTICIPANTS: 19 avoidable causes of death among men and women aged 0-64 years. Mortality and population data were derived from the WHO mortality database; and perinatal mortality rates, from the Health for All statistical database. Main results: Avoidable mortality declined (1980-1997) in all the countries except Hungary. The difference between the trends in avoidable and non-avoidable mortality was small (-2.4% compared with -1.5%) and diminished over time. The largest trend variations between countries are attributable to causes mainly or partly amenable to prevention. For five of the 19 causes of death the international variations diminished over time. Various countries show trends that deviate significantly (p<0.003) from the mean trend. CONCLUSIONS: One explanation for the small and diminishing difference between avoidable and non-avoidable mortality is that some large avoidable causes show unfavourable trends. Another possible explanation is that the category of non-avoidable mortality is "polluted" by causes that have become avoidable with time. It is therefore suggested that Rutstein's lists of avoidable outcomes (1976) be updated to enable the appropriate monitoring of healthcare effectiveness. In countries that show unfavourable developments for specific avoidable causes, further research must unravel the causes of these trends.     

Current trends in perinatal mortality statistics at the New Jersey Obstetric Center

The study presents an overview of the changes in perinatal mortality rates at the Statewide Perinatal Center of New Jersey during the past decades. According to the data, the increase in the rate of cesarean sections from 4.5 percent to 17 percent, and the comparable reduction of the rates of manipulative intrapartum and extraction procedures, contributed significantly to the decrease of the perinatal mortality rates from 51/1000 to 17/1000 between 1971 and 1983. Of the new technical tools, those utilized for the evaluation of fetal well-being antepartum appeared to be more useful then those used intrapartum. On account of the high prevalence of genital infections in the population, the recent acceptance in the service of the use of invasive intrapartum technology, appears to have impacted unfavorably upon the perinatal mortality trends. The increased rate of births of premature babies, the widespread abuse of habit forming drugs in the community, and the routine use of procedures requiring artificial rupture of the membranes, probably all contributed to the rapid increase of the perinatal mortality rate in the Center from 15/1000 in 1986 to 28/1000 in 1988. It is concluded that perinatal care is a complex medical and social task. The overall result of the relevant efforts depends to a great extent upon the social environment, and the moral standing, educational level and motivation of the recipients.     

Perinatal mortality in the Netherlands: everyone's problem and yet no one's problem

In 1986, this journal published a paper showing that the rate of decline of perinatal mortality in the Netherlands was lower than in several other European countries. As a result, the Netherlands had lost its position as a country with one of the lowest perinatal mortality rates in the world. Since then, relatively little has happened to redress the situation, despite the fact that several studies have shown that the higher perinatal mortality rates are not due to registration artefacts, and that the quality of perinatal care in the Netherlands is lower than that in countries with lower perinatal mortality rates. In a recent analysis by the Rijksinstituut voor Volksgezondheid en Milieu (State Institute for Public Health and the Environment) it was estimated that between 20 and 25% of the difference between the perinatal mortality rates of the Netherlands and those of Sweden and Finland is due to the higher frequency in the Netherlands of five factors: multiple pregnancies (probably as a result of in-vitro fertilisation), smoking during pregnancy, pregnancies among non-western immigrants, no screening for congenital disorders, and (other) 'substandard' factors in perinatal care. Unfortunately, there are still no signs of a determined policy response. It seems that twenty years of working on the basis of the voluntary participation of many different organisations, and without clear leadership, have not produced the gain in perinatal mortality that would theoretically have been possible.     

Indices of birthweight-specific perinatal mortality in Germany from 1985 to 1999

A study of the trends in German perinatal data over the 15 years from 1985 to 1999 is complicated by the fact that the numbers from 1991 onwards represent the data for reunified Germany, whereas the numbers before 1991 give the data for former West Germany. The latest figure for the number of livebirths in Germany was 770744 in 1999 with a rate of low birthweight of 6.5% and a perinatal mortality rate of 0.62%. A constant increase in numbers of low-birthweight infants was observed, rising from 33531 in 1985 to 41145 in 1990 and from 47863 in 1991 to 50294 in 1999. This rise in low-weight births concerned mainly infants of <1500 g. In parallel, there was a decrease in early neonatal and infant mortality rates in all subgroups of low-birthweight infants except for the extremely small infants of <500 g where no clear tendency was observed over 15 years.     

State trends in infant mortality, 1968-83.

This paper presents an analysis of state trends in infant mortality rates (IMRs) for 1968-83. In order to take into account the large random error component associated with state IMRs, weighted least squares estimates are used to fit log-linear models to these trends. Using simulated data, these estimates are shown to be nearly unbiased and to provide valid significance tests. However, the power to detect changes in trend is rather limited, especially in small states. Using these methods, separate analyses of White IMRs in 49 states and non-White IMRs in 30 states were completed. Nine states are identified which had infant mortality trends less favorable than the national experience and 1981-83 rates more than 5 per cent above the national average.     

Ethnic differences in perinatal mortality--a challenge.

The perinatal mortality rates of mothers who delivered at St. Thomas's Hospital from 1969 to 1976 have been examined. The rate in the West Indian population was significant higher than in the United Kingdom white population. The increased West Indian mortality was confined to infants with a birth weight of more than 2.0 kg and a gestational age of more than 37 weeks. The relative risk of perinatal death for West Indian mothers compared with UK white mothers was 1.4 at birth weights of 2.5 kg to 2.9 kg, rising to 4.3 at 4.0 + kg. West Indian perinatal mortality in term babies of normal birth weight was higher in all maternal age and parity groups except parity 3, but the difference was greatest in women aged 30 or over. The African perinatal mortality rate was not significantly greater than the UK white rate although it followed the West Indian trends. Pre-eclampsia and forceps delivery were associated with a greatly increased perinatal mortality in West Indian babies. The excess West Indian mortality could not be explained completely by differences in the proportions of stillbirths and early neonatal deaths nor by the distribution of births by parity, maternal age, or social class. Possible explanations for the differences in mortality are discussed.     

Infant and perinatal mortality in Spain 1981–1991: Interprovincial variations in Autonomous Communities with extreme economic levels

The aims of the present study were to describe and compare infant, neonatal, postneonatal and perinatal mortality in aggregates of Spanish Autonomous Communities (AC) with higher and lower income, as well as to describe and compare their respective inequalities among the provinces constituting AC with similar (high or low) and with extreme economic levels, over the period from 1981 to 1991. The coefficient of variation (weighted by the number of births) has been used as the measure of interprovincial inequalities in mortality within each aggregate of AC and time trends in the average mortality rates and in their coefficients of variation have been analyzed using simple linear regression. The results of the study confirmed that the four mortality rates were all higher in the aggregate of AC of lower income than in that of higher income, and have fallen in both in a similar manner. Thus the perinatal mortality rates for the lower and higher income aggregates of AC respectively were 17.3 and 12.5 per 1000 births in 1981, and 8.3 and 6.8 in 1991. The inequality in postneonatal mortality was dominant in the group of AC with a lower economic level whereas geographical inequalities in perinatal mortality predominated in the higher income group. The predominance of interprovincial inequalities in perinatal mortality when all the AC (with extreme economic levels) were considered suggest that economic factors are closely related to perinatal mortality.     

Five-decade international trends in the relation of perinatal mortality and congenital malformations: stillbirth and neonatal death compared.

The relation between long-term temporal trends in stillbirth and neonatal death rates and the congenital malformation frequencies in such deaths were analysed, using data from hospital-based European, USA, and Canadian reports published from 1950. In the last 50 years the overall perinatal mortality rate has fairly steadily improved, decreasing by 65-80%. This was accomplished by the control of some serious problems of early life. However, lingering disorders form an ever larger proportion of the causes of perinatal mortality. Among the prominent of these are congenital malformations, accounting for nearly 30% of perinatal deaths at present. However, this figure conceals important differences between stillbirths and early neonatal deaths. For example, although stillbirth and early neonatal mortality rates have decreased to similar extents during these years, congenital malformations, which were almost equally frequent causes of death in both of them at the beginning of this period, are now about twice as common in early neonatal (one week) deaths as in stillbirths. Other differences between them are in birthweight-related malformation frequencies and in characteristic arrays of malformations. The significance of these patterns and of some geographical variations, and the likelihood of continuing improvement in the stillbirth and early neonatal mortality rates are discussed.     

Infant,neonatal and postneonatal mortality trends in Andalucía,Spain, 1975-1989

BACKGROUND: Infant mortality and its neonatal and postneonatal aspects are important health indicators and thus warrant regular analysis even in developed countries where the rates thereof have dropped considerably. This study is aimed at describing the changes recorded in these rates in Andalusia over the past twenty-five years. METHODS: The annual infant, early and late neonatal and postneonatal mortality rates have been calculated for the 1975-1998 period. Poisson regression was used to estimate the annual percentages of change in the rates for the 1975-1986 and 1987-1998 periods, as well as for the entire 1975-1998 period. An analysis was also made of the proportional mortality rate due to infectious, respiratory, congenital causes, disorders having arisen during the perinatal period and all other causes, as well as the ratio for mortality rates due to disorders having arisen in the perinatal period and for all causes as a whole for the 1994-1998 four-year period as compared to the 1975-1979 period, in infant, neonatal (early and late) and postnatal periods. RESULTS: The greatest percentage drops were in early (6.38%) and late (4.6%) neonatal mortality. The ratio for mortality rates due to disorders having arisen in the perinatal period for the 1994-1998 and 1975-1975 periods is 10 for the postneonatal mortality rate, whilst it is under 1 for the late (0.63) and early (0.33) neonatal and infant (0.30) mortality. CONCLUSIONS: Mortality during the infant, early and late neonatal and postneonatal periods dropped sharply during the 1975-1998 period. The risk of death due to disorders arising during the perinatal period among children ranging from four weeks to one year of age (postneonatal period) rose tenfold during the 1975-1979 and 1994-1998 periods.     

Reinterpreting the effects of maternal smoking on infant birthweight and perinatal mortality: a multivariate approach to birthweight standardization.

Infants of women who smoke during pregnancy have lower birthweights and have been observed to have higher rates of perinatal mortality than infants of non-smokers. It is not clear whether this increased risk of mortality is due to an excess of small births among smokers or to an independent effect of smoking. Although infants of smokers have overall higher mortality rates than non-smokers, low birthweight (< 2500 g) infants of smokers have lower mortality rates than low birthweight infants of non-smokers. However, comparison of birthweight-specific mortality between two groups is problematic when there are differences in the birthweight distributions. Methods that have been developed to standardize for these differences by comparing mortality rates relative to their own mean do not allow for simultaneous control of confounding variables. Using data from over 13,000 births of women who participated in a prepaid health care plan we present a method to standardize for birthweight while adjusting for variables that may confound the relationship between maternal smoking and perinatal mortality. After controlling for race, maternal age, education, parity, and number of cigarettes smoked, we found that 85% of the increased mortality due to smoking was attributable to an excess of small births in the birthweight distribution of offspring of smoking mothers, while 15% was due to higher birthweight-specific mortality at almost all standardized birthweights. Contrary to previous reports, we found that low birthweight infants of smoking mothers are at higher risk of perinatal mortality if a population-specific standard for birthweight is used.     

Government statistics of certified causes of perinatal mortality in Moscow and certain problems with its improvement

While preparing the Ninth Revision of the International Classification of Diseases, Injuries and Causes of Death (1970-1975), the World Health Organisation sought ways of improving the accuracy of statistics of perinatal mortality. A new Certificate of Cause of Perinatal Death, developed for use in all regions of the USSR and introduced there in 1974, was recommended for introduction in other countries. This was based on the reorganised and more clear-cut coding outlined in Chapter XV of ICD-9. Comparison of the perinatal death rates in 1975 with those in 1986 showed a fall from 25 to 20 per 1000 births, with changes in causes related to changes on classification. Cross-tabulation of multiple-cause perinatal death was made possible by coding maternal conditions affecting the fetus or newborn separately from fetal conditions originating in the perinatal period. Analysis of the results of tabulation of multiple-cause perinatal death in Moscow in 1986 proceeded to a proposed structure for a Basic Tabulation List allowing comparisons of the statistics of perinatal mortality.     

International infant mortality rates: bias from reporting differences.

International infant mortality statistics have caused concern in the United States, since the US ranking relative to other developed countries has declined since World War II. This paper suggests that there may be international differences in reporting of very-low-birthweight infants and perinatal deaths and that such reporting differences bias comparisons of national perinatal and infant mortality rates. Efforts must be made to adopt standard conventions for the inclusion of small, early infants and fetal deaths in rate calculations.     

Government statistics of certified causes of perinatal mortality in Moscow and certain problems with its improvement

Summary. While preparing the Ninth Revision of the International Classification of Diseases, Injuries and Causes of Death (1970–1975), the World Health Organisation sought ways of improving the accuracy of statistics of perinatal mortality. A new Certificate of Cause of Perinatal Death, developed for use in all regions of the USSR and introduced there in 1974, was recommended for introduction in other countries. This was based on the reorganised and more clear-cut coding outlined in Chapter XV of ICD-9. Comparison of the perinatal death rates in 1975 with those in 1986 showed a fall from 25 to 20 per 1000 births, with changes in causes related to changes on classification. Cross-tabulation of multiple-cause perinatal death was made possible by coding maternal conditions affecting the fetus or newborn separately from fetal conditions originating in the perinatal period. Analysis of the results of tabulation of multiple-cause perinatal death in Moscow in 1986 proceeded to a proposed structure for a Basic Tabulation List allowing comparisons of the statistics of perinatal mortality.     

Perinatal mortality in Shanghai: 1986-1987.

The incidence of, and risk factors associated with, perinatal mortality in Shanghai during 1986-1987 are examined using data from a multi-site study conducted in 29 hospitals. The overall perinatal mortality rate was 14.96 per 1000 births. The mortality rates of antepartum fetal death, intrapartum fetal death and early neonatal death were 5.97, 2.06 and 6.94 per 1000 births, respectively. The perinatal mortality rates increased in winter and late spring. Male neonates were 1.5 times more likely to die than females. Low birthweight and preterm infants had 15 to 80 times higher risk of perinatal death. Higher parity, multiple pregnancy, and maternal age greater than or equal to 35 years were the risk factors for perinatal mortality. Asphyxia, cord complications, and congenital malformations were found to be the major causes of perinatal deaths. Comparison of mortality rates between Shanghai and the US suggests that the shortage of advanced technology in perinatal care (e.g. neonatal intensive care units) is a major obstacle to the reduction of perinatal mortality in Shanghai.     

Birthweight and perinatal mortality: paradoxes,social class,and sibling dependencies

BACKGROUND: Birthweight distributions among second-born infants depend on the birthweights of older siblings, with implications for weight-specific perinatal mortality. We wanted to study whether these relations were explained by socioeconomic levels, and to study time trends in a situation with decreasing perinatal mortality rates. METHODS: Births in the Norwegian Medical Birth Registry from 1967 to 1998 were linked to their mothers through their national identification numbers. The study population was 546 688 mothers with at least two singletons weighing >/==" BORDER="0">500 g at birth. Weight-specific perinatal mortality for second-born siblings in families with first-born siblings in either the highest or the lowest birthweight quartile was analysed. Maternal education and cohabitation status were used as measures of socioeconomic level. RESULTS: For all 500-g categories below 3500 g, mortality rates were significantly higher among second-born infants with an older sibling in the highest rather than the lowest weight quartile. This pattern was the same across three educational levels. The exclusion of preterm births did not change the effect pattern. A comparison of perinatal mortality among second siblings in terms of relative birthweight (z-scores) showed a reversal of the relative risks, although these were only significantly different from unity for the smallest infants. Conclusion The crossover in weight-specific perinatal mortality for second siblings by weight of first sibling is largely independent of socioeconomic level, and is not weakened by the decreasing perinatal mortality rates in the population over time. Family data should be taken into consideration when evaluating the risk of adverse pregnancy outcome relating to weight.     

Racial and ethnic differences in perinatal mortality: the role of fetal death

PURPOSE: We investigate whether variations in infant mortality rates among racial/ethnic groups could be explained by variations in fetal mortality rates where relatively higher infant mortality rates may correspond to lower fetal mortality rates due to possible systematic differences in reporting of fetal death compared to live births. METHODS: Using US perinatal data from 1995 to 1999, we calculated crude mortality rates, birth weight-specific fetal and hebdomadal mortality rates, risks of perinatal death, and the risk of being classified as a fetal death versus other period death among infants born to Non-Hispanic White, Non-Hispanic Black, and Hispanic mothers. RESULTS: Two-fold disparities between Whites and Blacks persist for all mortality categories. Black low birth-weight deliveries, compared to Whites, have perinatal advantages in both fetal and hebdomadal periods. Hispanics were less likely than Whites to be reported as a fetal versus a hebdomadal death. CONCLUSIONS: While these data suggest some underreporting of Black fetal deaths, they provide little evidence that Black-White disparities in infant mortality are a function of variations in classifying a death occurring at delivery as either a fetal death or as a live birth-infant death. These data suggest that the lack of a White-Hispanic disparity in fetal mortality rates may be influenced by underreporting.