The effect of child mortality experience on subsequent fertility: in Pakistan and Bangladesh

Summary This paper presents an empirical analysis of the effects, behavioural and biological, of child mortality experience on subsequent fertility in two South Asian Islamic nations. Data for the investigation came from retrospective pregnancy histories of 2,910 currently married women interviewed in the Pakistan National Impact Survey (1968-69) and from longitudinal vital registration data (1966-2070) of 5,236 women residing in a rural area of Bangladesh collected by the Cholera Research Laboratory. The aim of this study was to assess the importance of the child-replacement motivational response to child death experience after biological effects have been controlled adequately. A common approach employed previously has been to examine cumulative fertility according to child death experience. In Pakistan and Bangladesh, a consistently positive relationship was demonstrated between the number of children ever born and the number of child deaths. This method, however, did not exclude the inverse relationship, the influence of fertility on mortality, nor did it dissect out behavioural from biological effects. Utilizing a measure of subsequent fertility, live-birth-to-live-birth intervals, the study further illustrated another common pitfall. Since the risk of infant death, which leads to shorter birth intervals, is associated with the mother's reproductive history, women with child mortality experience are more likely to experience shorter intervals because of the biological effect of subsequent infant death. Behavioural influences may, therefore, be observed by considering only those birth intervals in which the first-born child survives to the end of the interval. With these limitations controlled, very few, if any, behavioural influences were noted in the Pakistan and Bangladesh data. Median birth intervals in Pakistan varied between 35-43 and 41-42 months, increasing with parity. Within each parity group, no consistent difference was observed between women with and without previous child loss. In Bangladesh, the median birth interval for all women with a surviving infant was 37-2 months. This was shortened to 24-31 months by an infant death. When intervals with infant deaths were excluded, little or no behavioural influence was detected among women of the same parity, but with varying levels of previous child loss. Even without behavioural effects, elimination of infant mortality in Bangladesh would reduce fertility by prolonging the average period of post-partum sterility. In the Bangladesh setting, however, the size of the effect was only about four per cent. This modest effect, more-over, was counterbalanced by an overall increase of net reproduction by seven per cent due to better survivorship of infants.     

Trends in fertility level in the Union of Soviet Socialist Republics during the years of Soviet rule

The birth rates of the USSR within its present boundaries are reconstructed for the period 1918-1940 on the basis of incomplete data and taking into consideration several changes in frontiers. Estimates for the years 1941-1945 are derived from data on school attendance during the 1949-1954 period, as well as from data provided by the censuses of 1959 and 1970 concerning cohort survival. Deriving an "effective fertility rate," which adjusts for the mortality wastage of young children, discussion focus is on fertility trends until 1976 and the changes in age patterns of reproduction at the national level and in the various republics. During the 1918-1940 period, the birth rate in the USSR never fell below 30/1000 and never exceeded 45/1000. There was a significant drop in the birth rate in the 1931-1936 period, and this is attributable to the problems of the period of collectivization and to the large-scale processes of migration involved in the country's industrialization. After the late 1940s, the overall birth rate in the USSR stabilized at a level of 25-27/1000, but from 1960 onwards, there was a steady decline in the rate. The level reached its lowest in 1969 and then rose somewhat. This increase reflects the transient influence of changes in the age-marriage structure of the population and in the "timetable" of births. A comparison of the present fertility level with the level in the 1920s indicates that the birth rate has declined by a factor of approximately 2.5, but in evaluating this decline the sharp decline in mortality, particularly infant mortality, must also be considered. The child mortality level in prerevolutionary Russia was very high. The overall mortality rate for the 20 provinces of European Russia in 1920-1922 was 33.2/1000, namely, 1/4 higher than it was before the Revolution. In subsequent years infant mortality continued at a high level and was 18.2% in 1940. In the last 25 years mortality in children under age 5 has markedly declined. In 1976 the overall birth rate was 18.5/1000 and the "effective" birth rate was 18.0/1000. The practice of birth control in families is spreading in various ways. In some cases the proportion of married couples using family planning is increasing, while in other cases couples already using birth control are beginning to use it after the birth of a child lower in birth order. In most areas of the country birth control is being practiced predominantly in such a way as to keep families down to 1 or 2 children. For the whole of the USSR in 1973-1974, the gross reproduction rate was 1.178, while the net rate was 1.118. Although there is ample population replacement in the country as a whole, in a number of republics even mere replacement is threatened.     

Changes in fertility patterns can improve child survival in Southeast Asia

This analysis of 1988 Philippine Demographic Survey data provides information on the direct and indirect effects of several major determinants of childhood mortality in the Philippines. Data are compared to rates in Indonesia and Thailand. The odds of infant mortality in the Philippines are reduced by 39% by spacing children more than two years apart. This finding is significant because infant mortality rates have not declined over the past 20 years. Child survival is related to the number of children in the family, the spacing of the children, the mother's age and education, and the risks of malnutrition and infection. Directs effects on child survival are related to infant survival status of the preceding child and the length of the preceding birth interval, while key indirect or background variables are maternal age and education, birth order, and place of residence. The two-stage causation model is tested with data on 13,716 ever married women aged 15-49 years and 20,015 index children born between January 1977 and February 1987. Results in the Philippine confirm that maternal age, birth order, mortality of the previous child, and maternal education are directly related to birth interval, while mortality of the previous child, birth order, and maternal educational status are directly related to infant mortality. Thailand, Indonesia, and the Philippines all show similar explanatory factors that directly influence infant mortality. The survival status of the preceding child is the most important predictor in all three countries and is particularly strong in Thailand. This factor acts through the limited time interval for rejuvenation of mother's body, nutritional deficiencies, and transmission of infectious disease among siblings. The conclusion is that poor environmental conditions increase vulnerability to illness and death. There are 133% greater odds of having a short birth interval among young urban women than among older rural women. There is a 29% increase in odds for second parity births compared to third or higher order parities. Maternal education is a strong predictor of infant survival only in the Philippines and Indonesia. Adolescent pregnancy is a risk only in Indonesia. Socioeconomic factors are not as important as birth interval, birth order, and maternal education in determining survival status.     

Rural–Urban Migration and Cross-National Variation in Infant Mortality in Less Developed Countries

The relationship between migration and child health in individual countries is well known, but the cross-national variation in this relationship is largely untested. Using Demographic and Health Survey (DHS) data from 52 medium and low income countries, this study examines the effect of rural–urban migration on infant mortality and whether its effect varies cross-nationally. A secondary objective is to determine whether there is a relationship between the time a child is born in the migration process and infant mortality. Hypotheses are developed on the basis of competing theories on the relationship between migration and health. There are modest, but significant cross-national effects of rural–urban migration on infant mortality, which were better revealed in the presence of family- and child-level variables. The results also show that the unadjusted effects of rural–urban migration are quite substantial, but were largely accounted for by family- and child-level factors including education, socioeconomic status (SES), marital status, birth order, maternal age at child’s birth, and inter-births intervals. The results largely point to a selection process, which is further confirmed by results showing that the hazards of infant death increase with length of urban residence. Programs that target increasing maternal education, improving household SES, and lengthening interbirth intervals would therefore greatly benefit child survival in less developed countries.     

The effects of pregnancy spacing on infant and child mortality in Matlab, Bangladesh: how they vary by the type of pregnancy outcome that began the interval

Using high-quality longitudinal data on 125,720 singleton live births in Matlab, Bangladesh, we assessed the effects of duration of intervals between pregnancy outcomes on infant and child mortality and how these effects vary over subperiods of infancy and childhood and by the type of outcome that began the interval. Controlling for other correlates of infant and child mortality, we find that shorter intervals are associated with higher mortality. Interval effects are greater if the interval began with a live birth than with another pregnancy outcome. In the first week of the child's life, the effects of short intervals are greater if the sibling born at the beginning of the interval died; after the first month, the effects are greater if that sibling was still alive. Many relationships found are consistent with the maternal depletion hypothesis, and some with sibling competition. Some appear to be due to correlated risks among births to the same mother.     

Two and a half centuries of demographic history in a Bavarian village

Abstract A village genealogy containing family histories of couples married between 1692 and 1939 serves as the basis for a study of the demographic history of a Bavarian village. The past patterns of marriage, re-marriage, widowhood, illegitimacy, bridal pregnancy, marital fertility, family size, and birth intervals are examined. Both the age at marriage and illegitimacy increased and then declined during the nineteenth century, apparently in response to changes in restrictive marriage legislation. Differences in fertility for occupational groups were insignificant. Marital fertility remained extremely high before 1900 suggesting the absence of any substantial family limitation within marriage. A rise in marital fertility that occurred during the last half of the nineteenth century appears to result from a change in breast-feeding customs. The actual number of children surviving to maturity for most couples was kept quite low, however, through late marriage and high infant mortality. Only during the twentieth century are substantial declines in infant mortality and fertility evident.     

Birth Intervals and Childhood Mortality in Rural Bangladesh

This study investigates the relationship between birth intervals and childhood mortality, using longitudinal data from rural Bangladesh known to be of exceptional accuracy and completeness. Results demonstrate significant but very distinctive effects of the previous and subsequent birth intervals on mortality, with the former concentrated in the neonatal period and the latter during early childhood. The impact of short birth intervals on mortality, however, is substantially less than that found in many previous studies of this issue, particularly for the previous birth interval. The findings are discussed in terms of the potential for family planning programs to contribute to improved child survival in settings such as Bangladesh.     

Birth-baptism intervals in 68 Lancashire parishes, 1646-1917

This article examines the birth/baptism interval in 68 Anglican parishes. It provides a continuous annual record from 1646 to 1917 thereby augmenting previous studies in which periods such as the 1640s, the mid-eighteenth and late-nineteenth centuries have been sparsely represented. During the seventeenth century intervals remained stable, but afterwards they increased with many parishes experiencing late baptism. Evidence is also presented to support the view that serious epidemic illness could result in shortening of the interval while population increase or a change of incumbent could lead to a lengthening of the interval.     

Risk Factors for Infant Mortality in Nineteenth-Century Sweden

This study examines risk factors for infant mortality using individual-level data from a sample of parishes in northern Sweden in the nineteenth century. Sweden is of particular interest because of its unusually regular pattern of infant mortality decline during the century. We follow a sample of women longitudinally through their successive pregnancies and observe the mortality experience of each child. Exploratory and multivariate logistic regression analyses reveal an important intra-familial dimension to infant mortality that appears from the early stages of a woman's reproductive career. In addition, multivariate analyses by birth-order group suggest that ignoring intra-familial correlations of infant mortality may result in incorrect inferences. Siblings' shared probabilities of dying as infants suggest that high-birth-order children were not necessarily disadvantaged in any systematic way.     

Socioeconomic Inequalities in Infant Mortality in Egypt: Analyzing Trends Between 1995 and 2014

This paper analyses the trend of the socioeconomic inequalities in infant mortality rates in Egypt over the period 1995–2014, using repeated cross-sectional data from the National Demographic and Health Survey. A multivariate logistic regression and concentration indices are used to examine the demographic and socioeconomic correlates of infant mortality, and how the degree of socioeconomic disparities in child mortality rates has evolved over time. We find a significant drop in infant mortality rates from 63 deaths per 1000 live births in 1995 to 22 deaths per 1000 live births in 2014. However, analyzing trends over the study period reveals no corresponding progress in narrowing the socioeconomic disparities in childhood mortality. Infant mortality rates remain higher in rural areas and among low-income families than the national average. Results show an inverse association between infant mortality rates and living standard measures, with the poor bearing the largest burden of early child mortality. Though the estimated concentration indices show a decline in the degree of socioeconomic inequality in child mortality rates over time, infant mortality rate among the poor remains twice the rate of the richest wealth quintile. Nonetheless, this decline in the degree of socioeconomic inequality in child mortality is not supported by the results of the multivariate logistic regression model. Results of the logistic model show higher odds of infant mortality among rural households, children who are twins, households with risky birth intervals. We find no statistically significant association between infant mortality and child’s sex, access to safe water, mothers’ work, and mothers’ nutritional status. Infant mortality is negatively associated with household wealth and regular health care during pregnancy. Concerted effort and targeting intervention measures are still needed to reduce the degree of socioeconomic and regional inequalities in child health, including infant mortality, in Egypt.     

The effects of infant mortality on fertility revisited: new evidence from latin america

In this paper, we examine empirical evidence for a relation between infant and child mortality and fertility in Latin American countries from 1920 to 1990. We investigate the relation at several levels of aggregation and evaluate the extent to which evidence at one level is consistent with evidence at other levels. We first examine aggregate cross-country information over several decades, a type of data typically used in past research on the topic. We also examine yearly series of births, deaths, infant deaths, and socioeconomic indicators for selected countries to track the association between short-term fluctuations in fertility and infant mortality. Finally, we use micro-level data from the Demographic and Health Surveys (DHS) to assess the relation between fertility and child mortality from individual reproductive histories. The evidence we assemble from these different data sets is remarkably consistent and suggests small positive effects of infant mortality on fertility. These effects, however, may be too small to support the hypothesis that changes in child mortality are of more than modest importance in the process of fertility decline in Latin America in the late twentieth century.     

Parental underinvestment: A link in the fertility-mortality continuum

Selective parental investment in siblings has been used to describe differential mortality rates. Using data from 986 Filipino women who had an average of 4.8 live births, a LISREL and six sets of regression models support the hypothesis that fertility is linked to underinvestment and that mortality, as a consequence, is linked to high birth order. The analysis also identifies intervening factors associated with this relationship. Age of mother at childbirth showed a strong influence on the relationship of birth order and infant and child mortality; correlations are stronger among older than youger mothers. However, even after the effect of age of mother at childbirth was partialled out, the effect of birth order on infant and child mortality remained significant and substantial. The conclusion is that parental underinvestment represents a link between fertility and mortality during infancy and early childhood that has not been described previously. Policy makers appear to have overlooked parental underinvestment in favor of more obvious economic and health mediators.     

Birth Intervals and Health in Adulthood: A Comparison of Siblings Using Swedish Register Data

A growing body of research has examined whether birth intervals influence perinatal outcomes and child health as well as long-term educational and socioeconomic outcomes. To date, however, very little research has examined whether birth spacing influences long-term health. We use contemporary Swedish population register data to examine the relationship between birth-to-birth intervals and a variety of health outcomes in adulthood: for men, height, physical fitness, and the probability of falling into different body mass index categories; and for men and women, mortality. In models that do not adjust carefully for family background, we find that short and long birth intervals are clearly associated with height, physical fitness, being overweight or obese, and mortality. However, after carefully adjusting for family background using a within-family sibling comparison design, we find that birth spacing is generally not associated with long-term health, although we find that men born after very long birth intervals have a higher probability of being overweight or obese in early adulthood. Overall, we conclude that birth intervals have little independent effect on long-term health outcomes.     

The cocos-keeling islands: A demographic laboratory

The Cocos Islands, which are situated in the Indian Ocean approximately halfway between Colombo and Fremantle, were first peopled early in the nineteenth century and were gradually developed as a very isolated coconut plantation with a labour force consisting partly of persons of Malay stock descended from the original group of settlers and partly of Bantamese contract labourers from Java. As the Cocos-born population increased in size, the dependence on contract labour decreased and, before the end of the century, all immigration ceased. The 1947 Malay population of the islands was about 1,800.

The islands are fascinating from a demographer's point of view because there was a virtually complete registration of live births, deaths and marriages and a partial registration of stillbirths. With these registration records it was possible to construct the life history of every individual from birth, through infancy and childhood to marriage, and thence through fatherhood or motherhood to death.

The picture revealed by an analysis of these records is that of a population with very high fertility and with mortality at a high level before the first World war and at a medium level after that war. Crude birth rates varied between 50 and 60 per thousand population during the period 1888 to 1947. Crude death rates were between 30 and 40 per thousand population until 1912 but under 2.0 per thousand population after 1918.

Most Cocos girls married before reaching the age of 20 and there were an average of between eight and nine live births per woman living through the childbearing period. There was a steady decline in the average number of live births with advancing age at marriage from age 16 onwards. A significantly high proportion of those dying in the middle of the childbearing period had never married, but the fertility of those marrying at an early age (14, 15 and 16) and dying before reaching the age of 36 was slightly higher than that of those who married at a similar age and survived. Women who survived to the age of 55 were of higher fertility than those who died between the ages of 40 and 55. An analysis of birth intervals revealed significant differences (a) between birth intervals after a stillbirth or after a live birth in which the child died in early infancy, and birth intervals after a live birth in which the offspring survived for longer than 0.4 years, and (b) between the interval from first to second birth and the subsequent birth intervals. There was a difference of almost exactly a year between the average birth interval after a stillbirth or live birth ending in a neo-natal death and the average birth interval after the birth of a child surviving to age 2; there was a similar difference of a year between corresponding median birth intervals.

From 1888 to 1912 infant mortality was well above 300 per thousand. After 1918 infant mortality averaged rather under 100 infant deaths per 1,000 live births. The reduction in infant mortality rates was accompanied by an increase in the mortality of children aged 1 to 4, and the heavy incidence of mortality at these ages after 1918 is the most striking feature of the analysis of mortality by age. Whilst mortality in infancy fell much more heavily on males than on females, early childhood mortality was much higher in Cocos for girls than for boys. The life table computed for the period 1918 to 1947 indicated a life expectancy of about 50 years for males and 47 years for females.     

Infant death clustering in families: magnitude, causes, and the influence of better health services, Bangladesh 1982-2005

This analysis of infant mortality in Bangladesh focuses on explaining death clustering within families, using prospective data from a rural region in Bangladesh, split into areas with and without extensive health services (the area covered by the International Centre for Diarrhoeal Disease Research and the comparison area, respectively). The modelling framework distinguishes between two explanations of death clustering: (observed and unobserved) heterogeneity across families and a causal 'scarring' effect of the death of one infant on the survival chances of the next to be born. Keeping observed and unobserved characteristics constant, we find scarring in the comparison area only. There the likelihood of infant death is about 29 per cent greater if the previous sibling died in infancy than otherwise. This effect mainly works through birth intervals: infant deaths are followed by shorter birth intervals, which increases the risk of infant death for the next child.     

The impact of childhood mortality on Fertility in six rural Thanas of Bangladesh

In this article, we examine the relationship between child mortality and subsequent fertility using prospective longitudinal data on births and childhood deaths occurring to nearly 8000 Bangladeshi mothers observed over the 1982-1993 period, a time of rapid fertility decline. Generalized hazard-regression analyses are employed to assess the effect of infant and child mortality on the hazard of conception, with controls for birth order and maternal age and educational attainment. Results show that childhood mortality reduces the time to subsequent conception if the death occurs within a given interval, representing the combined effect of biological and volitional replacement. The time to conception is also reduced if a childhood death occurs during a prior birth interval, a finding that signifies an effect of volitional replacement of the child that died. Moreover, mortality effects in prior birth intervals are consistent with hypothesized insurance (or hoarding) effects. Interaction of replacement with elapsed time suggests that the volitional impact of child mortality increases as the demographic transition progresses. This volitional effect interacts with sex of index child. Investigation of higher-order interactions suggests that this gender-replacement effect has not changed over time.     

The child survival hypothesis

Summary Because of current interest in the child survival hypothesis, we have reviewed available evidence bearing upon the relationships of infant and child mortality to fertility and contraceptive behaviour. The evidence is drawn from time series data for local and national vital events, from special in-depth studies of the infant mortality-fertility relationships in family formation, and from service statistics from health and family planning programmes. As a result of this review, we suggest five clarifications which should be made in redefining the child survival hypothesis and assessing its potential programme implications. The child survival hypothesis states that improved child survival will contribute to increased family planning motivation and consequent fertility decline. The evidence presented here suggests that the effect is not automatic and probably not a necessary pre-condition for fertility decline. There is certainly not a reflexive one-to-one replacement, but a partial effect may still be important. In the clearly demonstrated reduction in inter-pregnancy intervals after a child death, the major component is undoubtedly the removal of the biological protection of lactational amenorrhoea. A separate but somewhat smaller effect has been demonstrated in situations where lactation did not seem to have been the explanation. It is expected that increased child survival will contribute to fertility decline mainly in countries experiencing rapid mortality decline and population growth. The replacement of children who die is probably not so much 'volitional' as a result of alterations in sub-conscious expectations. It is apparent that in traditional agrarian populations, few direct and manipulable means of influencing motivation for fertility limitation are available, and, therefore, it must be stressed that integrated health and family planning programmes do provide opportunities for immediate programme development. By making parents aware of improved changes of survival through health services in which they develop confidence, the spontaneous linkages between mortality and fertility can presumably be reinforced. Family planning services must be provided as an essential initial step in programme development, but they can be made more effective, as well as politically more acceptable if appropriately integrated with maternal and child health and nutrition services.     

Further evidence on the decline in infant mortality in pre-industrial England: North Shropshire, 1561-1810

Summary There is growing evidence of a substantial decline in infant mortality in England from the late seventeenth century onwards. This trend is examined in detail using data from the parish registers of a group of rural parishes in North Shropshire. A major change in the whole pattern of first-year mortality during the period 1661-1810 is indicated, its main features being an increase in mortality between the ages of six and eleven months, and a marked fall in mortality during the first three months of life. Examination of the seasonal pattern of infant mortality shows very heavy mortality among young infants in the winter, presumably from respiratory causes, during the period before 1700. It is suggested that a fall in the number of deaths from these causes was the main reason for the decline in infant mortality since the late seventeenth century.     

Fertility in black Africa

The number of children per woman is between 6 and 7 children in Black Africa. Infertility and poor fertility existing in certain regions of Africa only appear in results concerning central Africa. 6-10% of births occur in women between the ages of 40 and 50. It must be noted that the goal of the majority of societies in Black Africa is to have numerous descendants. Factors of fertility in Africa examined are: precocious marriage, a long period of exposure to the risk of pregnancy, birth spacing and pathological infertility. The paper also discusses modern contraception and birth control, the improvement of sanitation conditions as part of the battle against infertility and infant mortality, combating infertility, decreasing infant mortality and governmental attitudes toward fertility control. Despite the efforts of several private and governmental agencies to promote family planning, progress in Africa has been modest. In the majority of Black African countries, women do not have access to contraception. In rural areas, the absence of an administrative infrastructure prevents diffusion of information and access to contraception. Improving general health conditions has 2 consequences on fertility: it reduces infertility due to diseases that cause sterility and it reduces infant mortality which affects birth intervals. So far birth control has only been successful among the very educated women. However, a great potential for more users exists.