Late Fetal Mortality Research Articles

鹿児島県における乳幼児死亡率の減少について

The secular changes and regional differences in perinatal, infant and early childhood mortality rates were studied for the period 1967 through 1986 using the health statistics issued by the Kagoshima prefectural government. The inter-relation of these mortality rates was also discussed. The following findings were made. 1) The infant mortality rate and early childhood mortality rates have generally declined progressively in the course of a 20-year period 1967 through 1986, the decrease was much more marked in infant mortality rate than in early childhood mortality rates and much greater in the first 15 years than afterward. The current low rates of infant mortality suggest that further decrease will be slower or difficult to achieve . Since 1980, in particular, the 1-year-old mortality rate has practically increased rather than stagnated. Then, a hypothesis was proposed that the increased rate in 1-year-old mortality was one of the causes of the decline in infant mortality rate by delaying deaths into the post-infant period. The late fetal death rate has also declined over the study period, the decrease was consistent with the pattern of infant mortality rate. 2) There were no marked differences between males and females for the changing patterns in infant and early childhood mortality rates. However, considerable differences in these mortality rates between male and female infants existed, in that male infants had consistently higher rates of mortality as compared with female infants . 3) Among 16 community-bases regional groups within the health center's jurisdiction, the income level was inversely correlated with both infant mortality rate and 1-4 year mortality rate. This correlation was significant for female infants but not for male infants. This fact raised a quetion whether the beneficial effects of urbanization in local communities on the infant and early childhood mortality rates were shown firstly among male infants. In contrast, fetal component of perinatal mortality was inversely correlated with female infant mortality rate but not with male infant mortality rate. The lower mortality rate reported for female infants may be partly attributed to the poor registration of infant deaths, since eraly neonatal deaths are sometimes reported as fetal death.

Countrywide analysis of perinatal outcome.

The computer laboratory of the Research Institute for the Care of Mother and Child in Prague performs annually a countrywide analysis of perinatal outcome in order to obtain a background for the preparation of the optimal strategy for improving perinatal care in CSR in the future. The total as well as weight specific perinatal mortality rate further sub-divided into early neonatal death rate and late fetal death rate and differentiated according to the birthweight, was correlated with the incidence of different factors influencing the perinatal mortality rate both countrywide and for each of the eight provinces of CSR. This way a correlation was found between some of the mentioned perinatal outcomes and e.g. instrumental equipment of obstetrical departments and neonatal intensive care units, frequency of caesarean sections, or transport of LBW newborns in incubators or "in utero" etc. The results of this analysis have proved that there still remain in some provinces opportunity for further decrease in perinatal mortality due to the incomplete observance of the two intervention strategies "Risk approach" and "New technology" which were introduced in the whole country during the last 10 years.

Perinatal morbidity and mortality in the Philippines.

AbstractThis study aims to identify the causes of perinatal morbidity and mortality at the University of the East Ramon Magsaysay Memorial Medical Center, and analyze the factors that lead to such results with the aim of improving them. Comparison is made with National Statistics and those of other countries. There were 4219 deliveries of 28 weeks and later or 1,000 grams and more during 1980–1982. Only 4057 were available for study. Results showed a neonatal death rate of 39/4015 (early neonatal death rate) or 9.7/1000 live births and a late fetal death rate of 42/4057 or 10.3/1000 total births with a perinatal mortality rate of 81/4057 or 19.99/1000 total births. Morbidity rate was 250/4015 or 62.3/1000 live births.Analysis of perinatal data correlated with maternal conditions, manner of delivery, age of gestation and birth weight was made. The study showed that results can be improved by early detection and treatment of maternal complications, but these are dependent on a multitude of socio‐economic and biological factors. The quality of mortality reporting was noted to be a source of difficulty in the study and is recommended for improvement.

Secular trend of twin concordance in late fetal death.

In the present paper the secular trend of twin concordance for late fetal death rate has been analysed. The results show that, while the correlation remains unchanged in MZ twins, it is greatly reduced in DZ twins. This renders untenable the assumption of comparable secular trends in the intrauterine environment of the two types of twins. An appropriate model is given for the estimation of the environmental (intrauterine) factors in late fetal concordance, under the assumption of a wide range of frequencies for unconditional lethals.

Fetal death during labor: An epidemiologic indicator of level of obstetric care

The effect of level of perinatal care on rates of intrapartum fetal death was studied in births of infants weighing > 1000 gm in New York City in 1976 to 1978. With potential confounding by birth weight, gestational age, and several other variables controlled, intrapartum fetal death rates decreased as intensiveness of care increased. Compared with births in level 3 maternity units (perinatal intensive care), births in Level 1 units (community hospitals) had a 61% excess risk of intrapartum fetal death (p < 0.01) and births in Level 2 units (intermediate level of care) had a 35% excess risk (p = 0.06). The effect of hospital level on intrapartum fetal death rates could not be attributed to differences in the classification of fetal deaths during labor across hospital levels, since no compensatory differences in late antepartum fetal death rates were found. Our findings in a total population are compatible with several studies carried out in single hospitals that have reported declines in intrapartum fetal death rates, especially in births more closely attended during labor. Fetal deaths that occur in labor, as contrasted with fetal deaths occurring before labor, constitute a perinatal outcome that is especially sensitive to level of obstetric care.

The Health Consequences of Teenage Fertility

A review of the literature on the health consequences of teenage pregnancy and childbirth shows remarkable similarity in findings from studies conducted in the United States, Canada, Britain, France and Sweden. In particular, results of studies conducted since 1970 have tended to indicate that the increased risk of maternal complications from pregnancy and delivery among teenagers--especially those older than 15--is associated more with socioeconomic factors than with the biological effects of age. Smaller differences in maternal mortality between teenagers and older women exist in England and Wales than in the United States and France; this finding suggests that England and Wales may have minimized the age or socioeconomic factors contributing to a difference in rates. Inadequate prenatal care may be a major cause of pregnancy-related complications for mothers, since teenagers in all countries are more likely than older mothers to seek care late in the pregnancy or not all. There is a very marked association between young age of mother and low birth weight in all countries. Sweden has the lowest rate of low birth weight at all maternal ages, and the United States generally has the highest. Some of the apparent effect of young maternal age on birth weight may be because the birth is likely to be the mother's first, and first births have a higher incidence of prematurity. As in the case of maternal health, inadequate prenatal care has been singled out as an important determinant of both prematurity and low birth weight. Late fetal death rates in the United States, England and Wales, and France are slightly higher among teenagers than among women in their 20s. In Canada and Sweden, however, no substantially increased risk for young women is found. Perinatal death rates, which one might expect to be influenced more by environmental factors than are late fetal deaths, show a more marked increase among infants of teenagers than do rates of late fetal deaths. Again, Sweden does not fit the pattern. Studies that separate data for young teens and older teenage mothers also indicate that increased perinatal and late fetal mortality rates may occur only among very young teenage mothers. There is no evidence of an overall increase in congenital malformations among babies born to teenagers. When individual birth defects are examined, some studies have shown increased rates of cardiovascular and central nervous system malformations among the children of teenage mothers.(ABSTRACT TRUNCATED AT 400 WORDS)

Sex differences in environmental sensitivity during growth and development

Data on sex differences in mortality, morbidity, growth under conditions of environmental stress, and growth responses to environmental improvement are reviewed to test the hypothesis that males are less buffered than females against the environment during growth and development. The hypothesis predicts that males should be more affected by environmental stress, and the strongest support for this is found in studies of the prenatal period. Under stressful conditions, males have higher late fetal mortality than females, and their fetal growth generally has been found to be more retarded. Investigations of postnatal responses to environmental stress have yielded much less consistent results, in large part because of the fact that male children are given preferential treatment in many societies. Results of studies of differences between the sexes in their response to environmental improvement are contradictory. During the prenatal peroid males seem to show a greater response to nutritional supplementation, while postnatal catch-up growth is usually greater in females. Similarly, some investigations report larger secular trends in males, while others have found larger increases in females. These contradictory findings can be reconciled with the hypothesis of greater male environmental sensitivity, but they illustrate the need to obtain more specific information on the environment to which males and females are subject before the hypothesis can be tested adequately.

Secular changes of the sex-ratio of stillbirths and early deaths in Italy: evidence for postponement of male specific risk.

Analyses of Vital Statistics from various industrialized countries have shown recent reduction of both the rate and sex-ratio of stillbirths. Two alternate explanations are conceivable for the finding: 1) the improvement of environmental conditions has actually reduced the male relative risk, 2) such an improvement has merely postponed late fetal mortality into early periods of extrauterine life. In order to discriminate between these two possibilities, both the secular trends of the sex-ratio of stillbirths and deaths in early infancy were analysed using Italian Vital Statistics. The results can be summarized as follows: 1) the sex-ratio of stillbirths continuously decreased during the examined period, from 1863 to 1979; 2) the sex-ratio of early deaths decreased until about 1920 and thereafter sharply increased. Therefore, Italian data seem to support the hypothesis of a postponement of late fetal deaths into early infant period.

Sex differences in human mortality: The role of genetic factors

This paper reviews evidence concerning genetic factors that influence sex differences in human mortality, with attention to the interactions between genetic and environmental factors. Some widely quoted earlier conclusions, for example, that males have consistently higher fetal mortality than females, are not supported by current evidence. For example, for late fetal mortality, males had higher rates than females in earlier historical data, but not in recent data for several advanced industrial countries. This reflects a changing balance between an inherently greater female vulnerability for one major type of late fetal mortality and inherently greater male vulnerability for several other types of late fetal mortality that have declined in importance as health care has improved. Males appear to be inherently more vulnerable than females to infant mortality, although the causes of this vulnerability are poorly understood. X-linked immunoregulatory genes appear to contribute to greater female resistance to infectious diseases. Despite these apparent inherent advantages for females, in some situations females have had higher infant mortality and higher infectious disease mortality than males, apparently due to environmental disadvantages for females, such as less adequate diet and health care. Inherent sex differences in reproductive physiology and anatomy contribute to higher female mortality for breast cancer and maternal mortality. For these causes of death, as for the other categories discussed, the death rates and thus the contributions to sex differences in total mortality vary considerably depending on environmental conditions. Several hypothesized contributions of sex hormones to sex differences in mortality are at present controversial due to contradictions and limitations in the available data. There may be effects of male sex hormones on sex differences in behavior which contribute to males' higher death rates for accidents and other violent causes. Women's endogenous sex hormones may reduce women's risk of ischemic heart disease. For both violent deaths and ischemic heart disease it appears that any genetic contributions to sex differences in mortality are strongly reinforced by the cultural influences that foster more risky behavior in males, including more use of weapons, employment in hazardous occupations, heavy alcohol consumption and cigarette smoking. It appears that these cultural influences on sex differences in behavior are widespread cross-culturally in part because of the effects of inherent sex differences in reproductive functions on the cultural evolution of sex roles. These examples illustrate the complexity and importance of interactions between genetic and environmental factors in determining sex differences in human mortality.

Rates of trisomies 21, 18, 13 and other chromosome abnormalities in about 20 000 prenatal studies compared with estimated rates in live births.

Data were analyzed on the results of 19675 prenatal cytogenetic diagnoses reported to two chromosome registries on women aged 35 or over for whom there was no known cytogenetic risk for a chromosome abnormality except parental age. The expected rates at amniocentesis of 47, + 21; 47, + 18; 47, + 13; XXX; XXY; XYY; and other clinically significant cytogenetic defects by maternal age were obtained from a regression analysis on the observed rates, using a first degree exponential model. After an adjustment for maternal age, these rates were compared with previously estimated rates by maternal age in live births. The rates of 47, + 21 at amniocentesis and live birth are approximately parallel, with the latter about 80% of the amniocentesis rates. The rates of 47, + 18 at amniocentesis and live birth are approximately parallel, with the live birth rates about 30% of the amniocentesis rates, consistent with high fetal mortality of 47, + 18 after amniocentesis. The rates of 47, + 13 at amniocentesis indicate an increase in maternal age that is not as marked as that previously estimated in live births. The rates at amniocentesis for XXX and XXY increase with maternal age, with the rates of XXY almost identical to those estimated previously in live births, suggesting no late fetal mortality of XXY. The rates of XYY show a slight decrease with maternal age also consistent with little late fetal mortality of XYY. No consistent trend with age is seen for the pooled group of other clinically significant defects.

Factors related to birth weight and perinatal mortality.

)reliable statistical reporting systems for a few countries extending back to World War II show that perinatal mortality rates have continuously fallen. To understand the reasons for this trend, 2 kinds of studies must be distinguished: studies which relate observed perinatal mortality rates or changes in rates to social, demographic, and other factors; and studies which set out "experimentally" to manipulate related factors and to study the effect on perinatal mortality rates. This discussion focuses exclusively on observational studies, covering factors associated with birth weight; components of the birth weight distribution; population studies; joint effects of several factors; birth weight, gestation, and mortality; and perinatal mortality. There are 2 distinct approaches to the study of birth weight: one that uses a threshold value, usally 2500 gm, and studies the proportion of births below that value; and one that studies differences in mean birth weight. Since, for many purposes, there is a particular interest in the very light babies, a direct measurement of their number is often the most appropriate approach. Which component procedures may be able to provide useful summary graduations of a birth weight distribution, their claims to represent substantive reality need ot be viewed critically. There are numerous studies of birth weight and perinatal mortality, but there are relatively few which have used adequate random sampling techniques allowing valid statements to be made about well defined populations. Attention is directed to results from a few large scale population studies, particularly the resultsof the 1958 British Perinatal Mortality survey. For both age and parity there was a change in the spread of birth weights as the mean birth weight rises, and this is reflected in the relationship between these factors and perinatal mortalty. The common practice of presenting percentiles of birth wieght for given gestation length is questionble since it suggests that babies at the same percentile value are in some sense equivalent. The use of birth weight alone gives a better prediction of perinatal mortality as can be seen by the manner in which the high mortality contours tend to become parallel to the gestation axis. For purposes of comparability, the 1973 World Health Organization (WHO) studies shows clearly that the use of separate late fetal death rates and neonatal death rates can be misleading. The use of a perinatal rate overcomes this problem. A table shows how perinatal mortality rates vary across the categories of several factors for Cuba, New Zealan, and Sweden in the 1973 WHO study. From the point of view of predicting high perinatal mortality risk, the data suggest that twins, high age and high parity mothers, and short interpregnancy intervals are common to all countries.

Recent changes in late fetal and neonatal mortality in New Zealand

The recent evolution of infant mortality rates in New Zealand and comparable countries is briefly reviewed. The proposition is advanced that significant improvements in the level of infant deaths may have been achieved independent of intervention by health services. Data are provided on variations in late fetal, neonatal and post-neonatal mortality according to raceof mother, marital status, maternal age, and cause. Some explanations are offered for the persistence of relatively high levels of post-neonatal mortality, and comment is made on countervailing tendencies in recent childbearing which make the task of improvement more difficult.

PERINATAL MORTALITY IN SWEDEN: Analyses with International Aspects

The perinatal mortality in Sweden has been decreasing during the last four decades. From available vital statistics in 1976 Sweden's figures are the lowest internationally. The decline continues and in 1978 the figure was as low as 10.0 per thousand. The five-year period 1973--1977 has been specially analysed using medical birth records from all births. Data from an international perinatal study in 1973 coordinated by WHO have been treated in the same way. With birth weight (BW) specific mortality rates in groups of 250 g it is shown that late fetal deaths (LFD) are related to BW only for high BW and that early neonatal deaths (END) are inversly related to BW. There is no sex difference in LFD but a marked male dominance in END, with one third higher rate for the boys. BW specific mortality rates in BW groups of 250 g, separated in LFD and END can be used as a tool for evaluating the quality of perinatal care. The influence oof factors related to patterns and standards of living is emphasized. It is suggested that perinatal mortality should be given in its two components separately late fetal death rates (LFD) and early neonatal death rates (END).

Plasma progesterone levels as an early pregnancy test in beef cattle

The accuracy of an early pregnancy test based on plasma progesterone concentrations was examined in a herd of 153 beef cows in which pregnancy status was confirmed by rectal examination three months after the end of an artificial insemination programme. At threshold progesterone levels of 1.50, 1.75 or 2.00 ng/ml the percentages of correct diagnoses in pregnant cows were 93.8, 93.8 and 90.1 and for non pregnant cows were 77.8, 79.2 and 84.7 respectively. At a threshold level of 1.50 ng/ml sixteen (22.2%) non pregnant cows were incorrectly diagnosed as pregnant, and on the basis of oestrus records could be classified into: 1. 1. Cows with cycle lengths (24 days) longer than the average. (Mean progesterone concentration 2.55 ± 0.64 ng/ml). 2. 2. Cows with mean cycle lengths of 39 days, in which apparent embryonic mortality had occurred (Mean progesterone concentration 3.47 ± 0.84 ng/ml). 3. 3. Cows not exhibiting oestrus during the remainder of the observation period, in which late embryonic or foetal mortality had apparently occurred (Mean progesterone concentration 4.89 ± 0.70 ng/ml).

Rural-urban differences in infant and child mortality among the Temne of Kolifa.

In this paper, the author's census data, collected in 1963, are used to compare infant and child mortality among the Temne of the rural chiefdom of Kolifa Mayoso and the nearby provincial town of Magburaka in central Sierra Leone. Problems in data collection and analysis are considered, and Temne cultural beliefs and practices which may influence early mortality levels are described. Comparative data from Sierra Leone, as well as other West African countries and the United States, are utilized with respect to late fetal (stillborn), perinatal, neonatal, post-neonatal, infant, and child mortality. Data relating to sex differences in early mortality and to higher mortality in cases of multiple births are included. The relatively high child mortality (probably weaning-related) in relation to infant mortality for both rural and urban series, and the lower urban than rural rates, exemplify the prevailing pattern for West Africa and, perhaps, for less developed areas generally.

Consanguinity and demography in some Chilean populations.

Spatial and temporal changes in the rates and the patterns of consanguinity are studied in some (indigenous as well as admixed) populations of Chile. Relationship between the variation of infant mortality and late fetal death rates with the degree of inbreeding is also explored. The need of a temporal study of these demographic variables is also emphasized to elucidate the influence of marriage structure or determined reproductive patterns on the genetic and demographic aspects within these populations.

The Fitness of the Human Zygote

SummaryThe fitness of human zygotes depends on both biological and demographic parameters. Some of the demographic parameters are changing at present in this country and accurate estimates of them are not available but this imprecision has no great bearing on the estimate of fitness offered below.Of 100 human zygotes, now, in this country, it is estimated that embryonic and early fetal loss (before the end of the 3rd month) accounts for 44; induced abortion, 7; late fetal loss (after the 3rd month), 4; and mortality between birth and maturity, 1½. Of the remaining 43½ who reach maturity, it is estimated that 8 fail to reproduce, leaving 35½ who do reproduce.The standard error of this estimate must be large because of the large standard error of the estimate of the incidence of natural reproductive wastage from which it was derived.

CIGARETTE SMOKING IN PREGNANCY

In a British population cigarette smoking during pregnancy increased the late fetal plus neonatal mortality rate by 28% and reduced birth weight by 170 g, and these differences persist even after allowing for a number of “mediating” maternal and social variables. A change in smoking habit by the end of the fourth month of pregnancy places a mother in the risk category appropriate to her changed habit. This evidence should have important implications for health education aimed at getting pregnant mothers to give up smoking.

Cigarette smoking in pregnancy: its influence on birth weight and perinatal mortality.

In a British population cigarette smoking during pregnancy increased the late fetal plus neonatal mortality rate by 28% and reduced birth weight by 170 g, and these differences persist even after allowing for a number of "mediating" maternal and social variables. A change in smoking habit by the end of the fourth month of pregnancy places a mother in the risk category appropriate to her changed habit. This evidence should have important implications for health education aimed at getting pregnant mothers to give up smoking.

Statistical Analysis of the Perinatal Mortality in Iwate Prefecture by Uemtsu's Indicator

Although the infant mortality rate in Iwate Prefecture was annualy reported to be the highest in the country in the period of ten years from 1955 to 1964, the perinatal mortality rate in the Prefecture was on a little lower level than the rate in all the country. From this fact, it is surmised that the factors influencing upon the perinatal mortality rate are somewhat different from the factors influencing upon the infant mortality. In order to elucidate the meaning of the perinatal mortality rate as a maternal and child health indicator, the author has performed statistical investigation. Perinatal mortality rate in each city, town, or village in Iwate Prefecture was calculated using the vital statistics of the Prefecture in 1955 and 1960, and the association between the perinatal mortality rate in 1955 and the rate in 1960, as well as the association between perinatal mortality rate or other maternal and child health indicator were studied. Perinatal mortality rate was also observed to be not always low in the areas where the health level was evaluated to be high by life expectancy or other indicator. Using the vital statistics of Japan in 1960, correlation coefficients between two of seven indicators, that is, late fetal mortality rate of 29 weeks or more, early neonatal mortality rate under one week, perinatal mortality rate, infant mortality rate, maternal mortality rate, Uematsu's Indicator (normal deviation of mortality) for female and the Indicator for male, were studied. And then, factor analysis was performed with the obtained correlation matrix. According to the result of factor analysis, seven indicators studied could he classified into next three groups; 1. Late fetal mortality rate of 29 weeks or more. 2. Perinatal mortality rate and maternal mortality rate. 3. Early neonatal mortality rate under one week, infant mortality rate, Uematsu's Indicator for female and Uematsu's Indicator for male. Taking these facts into consideration, it has been deducted, according to the author's opinion, that perinatal mortality rate is a useful indicator for evaluating maternal and child health level of the communities.