New evidence about effects of reproductive variables on child mortality in sub-Saharan Africa

There is still considerable uncertainty about how reproductive factors affect child mortality. This study, based on Demographic and Health Survey data from 28 countries in sub-Saharan Africa, shows that mortality is highest for firstborn children with very young mothers. Other children with young mothers, or of high birth order, also experience high mortality. Net of maternal age and birth order, a short preceding birth interval is associated with above average mortality. These patterns change, however, if time-invariant unobserved mother-level characteristics of importance for both mortality and fertility are controlled for in a multilevel–multiprocess model. Most importantly, there are smaller advantages associated with longer birth intervals and being older at first birth. The implications of alternative reproductive ‘strategies’ are discussed, taking into account that if the mother is older at birth, the child will also be born in a later calendar year, when mortality may be lower.     

Sibling loss and fertility desires in the high-mortality context of Peru

Despite demographers’ long-standing preoccupation with the effects of child mortality on women’s fertility desires, scholars continue to know little about the consequences of other pervasive mortality exposures. We use nationally representative data from the high-mortality context of Peru to examine whether the desire to have a(nother) child varies as a function of sibling loss and to assess heterogeneity in this association by women’s current number of children and a range of conditions related to siblings’ deaths. Women who have experienced sibling bereavement and have two or more children report higher odds of desiring another child. These effects are not contingent on the age or sex of the deceased sibling but are only significant if the sibling died during the respondent’s lifetime (not before). These findings highlight the theoretical and empirical import of investigating the relationship between fertility desires and a wider range of familial mortality exposures beyond own child mortality.     

Children as insurance

This paper presents a dynamic model of fertility decisions in which children serve as an incomplete insurance good. The model incorporates uncertainty about future income and the survival of children as well as a discrete representation of the number of children. It contributes to the understanding of the negative relation between fertility and education, shows why parents may demand children even if the return is negative, and explains why fertility might rise with increasing income when income is low and decrease when income is high. Furthermore, the model can account for the decline in fertility when the risk of infant and child mortality decreases. Finally, the implications for empirical tests of the demand for children are also examined. Received: 8 September 1998/Accepted: 9 June 1999     

Rethinking Historical Reproductive Change: Insights from Longitudinal Data for a Spanish Town

A set of linked reproductive histories taken from the Spanish town of Aranjuez between 1871 and 1950 is used to address key issues regarding reproductive change during the demographic transition. These include the role of child survival as a stimulus for reproductive change, the use of stopping and/or spacing strategies to achieve reproductive goals, and the timing of change. Straightforward demographic measures are used and robust results are achieved. Initial strategies of fertility limitation are shown to exist but are inefficient, are mostly visible during the latter part of the reproductive period, are designed mostly to protect families from the effects of increases in child survival, and are based almost entirely on stopping behavior. As mortality decline accelerates, strategies become much more efficient, are visible at the outset of married life, include spacing behavior, and eventually lead to important declines in completed family size. The results of this study have implications for our understanding of the demographic transition both in historical Europe and in other regions of the world.     

Health Interventions and Health Equity: The Example of Measles Vaccination in Bangladesh

Although the existence of socioeconomic differentials in infant and childhood mortality in developing countries is well established. little consensus exists as to the most effective approaches to reducing such differentials. This article utilizes longitudinal data from the Matlab study area in rural Bangladesh to investigate the impact of an efficacious child survival intervention—measles vaccination—on reductions in gender and socioeconomic differentials in childhood mortality. The article analyzes data from 16,270 vaccinated children and randomly matched controls, and evaluates their subsequent mortality risks. Proportional hazards analysis demonstrates that unvaccinated children from very poor families face more than a threefold higher risk of subsequent early child mortality, compared to vaccinated children from families of high economic status. While measles vaccination has little impact on mortality risks among children of higher economic status, the improvement in survival among children from poorer households is pronounced. The provision of measles vaccination markedly reduces mortality risks for poorer children—from over three times higher to just over 1.5 times higher relative to vaccinated children from wealthier families. The findings of this study are evaluated in terms of the potential of child survival interventions such as measles vaccination to promote greater health equity.     

Risk, uncertainty and family formation: The social context of poverty groups

Abstract Despite the assumptions of many demographers that the net returns from children for non-elite groups in underdeveloped areas are likely to be negative, high fertility persists in most of these societies. Both cultural and institutional explanations have been proposed to account for this. We attempt to provide some mediation between these competing models, by introducing the elements of risk and uncertainty as factors likely to induce poverty and lead works to opt for the 'high fertility, low quality' pattern of investment of time and money in family formation. Drawing upon the work of Wharton in subsistence agriculture practices, several alternative decision-making models are proposed to account for both the persistence of high fertility, and the declines that have been registered in selected areas, such as Taiwan and perhaps China. The empirical work of Mueller on Taiwanese expectations of returns on children and the concomitant variation in family-size preferences is consistent with the models proposed. Some implications for uncertainty and risk-reduction strategies in family planning and other social welfare programmes are drawn.     

Agency in Fertility Decisions in Western Europe During the Demographic Transition: A Comparative Perspective

We use a set of linked reproductive histories taken from Sweden, the Netherlands, and Spain for the period 1871–1960 to address key issues regarding how reproductive change was linked specifically to mortality and survivorship and more generally to individual agency. Using event-history analysis, this study investigates how the propensity to have additional children was influenced by the number of surviving offspring when reproductive decisions were made. The results suggest that couples were continuously regulating their fertility to achieve reproductive goals. Families experiencing child fatalities show significant increases in the hazard of additional births. In addition, the sex composition of the surviving sibset also appears to have influenced reproductive decisions in a significant but changing way. The findings offer strong proof of active decision-making during the demographic transition and provide an important contribution to the literature on the role of mortality for reproductive change.     

The Effect of Child Mortality on Contraceptive Use and Fertility in Colombia,Costa Rica and Korea

In this paper the question whether reproductive behaviour is consciously altered by the death of a child is answered by using World Fertility Survey data from Colombia, Costa Rica, and Korea. Alternative strategies are proposed by which women replace children who have died. They may choose to contracept for a shorter period following the death of a child, or they may cease using contraception. Each strategy is analysed separately for selected birth intervals and its effect estimated with loglinear techniques. It is found that the timing and nature of the response to child mortality appear to depend on the stage reached in a country's fertility transition.     

Child mortality and fertility decline: Does the Barro-Becker model fit the facts?

I compare the predictions of three variants of the altruistic parent model of Barro and Becker for the relationship between child mortality and fertility. In the baseline model fertility choice is continuous, and there is no uncertainty over the number of surviving children. The baseline model is contrasted to an extension with discrete fertility choice and stochastic mortality and a setup with sequential fertility choice. The quantitative predictions of the models are remarkably similar. While in each model the total fertility rate falls as child mortality declines, the number of surviving children increases. The results suggest that factors other than declining infant and child mortality are responsible for the large decline in net reproduction rates observed in industrialized countries over the last century. Financial support by the National Science Foundation (grant SES-0217051) and the UCLA Academic Senate is gratefully acknowledged. I thank Sebnem Kalemli-Oczan, Rodrigo Soares, and two anonymous referees for comments that helped to substantially improve the paper. Olesya Baker and Ilya Berger provided excellent research assistance. Responsible editor: Junsen Zhang.     

The Limits to Low Fertility: A Biosocial Approach

In light of 30 years of below‐replacement fertility in many industrialized societies, demographers are asking whether fertility could drop even further, or whether there is a “floor” below which it will not fall. A key unanswered question is whether there may be a variable biological component to fertility motivation which ensures that we continue to reproduce. Drawing on evidence from evolutionary biology, ethology, quantitative genetics, developmental psychobiology, and psychology, the article argues that our evolved biological predisposition is toward nurturing behaviors, rather than having children per se. Humans have the unique ability to be aware of such biological predispositions and translate them into conscious, but nevertheless biologically based, fertility motivation. It is likely that we have already reached the limits to low fertility since this “need to nurture,” in conjunction with normative pressures, ensures that the majority of women will want to bear at least one child. A sketch for a biosocial model of fertility motivation is outlined.     

Child mortality and reproductive behaviour in German village populations in the past: A micro-level analysis of the replacement effect

Abstract Reproductive histories of couples married during the eighteenth and nineteenth centuries in a sample of 14 German villages are analysed in order to answer several questions regarding the relationship between child mortality and reproductive behaviour. An effort is made through selection of cases and use of multiple classification analysis to eliminate or control non-volitional or otherwise confounding influences on the relationship between a couple's experience with child mortality and their fertility. The results do not provide a decisive answer to the question of whether, under a regime of otherwise presumed natural fertility, previous experience of child mortality affected subsequent reproductive behaviour. The evidence was much clearer in indicating that behaviour consistent with replacement efforts emerged or strengthened as family limitation spread. Finally, the results indicated that though it was not necessary for overall child mortality to decline before family limitation practices were adopted, couples with the most favourable child mortality experience were most likely to practise family limitation and to reduce their fertility. Child mortality appeared at least to impede, if not totally prevent, efforts to reduce the number of children ever born or to cease childbearing at an earlier age or at a given parity.     

Beyond infant mortality: gender and stillbirth in reproductive mortality before the twentieth century

Though it has been the largest component of reproductive mortality since its statutory registration in 1928, stillbirth has received little attention from historical demographers, who have relied on the more orthodox indicator of early human survival changes - "infant mortality". The exclusion of stillbirth hampers demographic analysis, underestimates progress in newborn vitality, and over-privileges post-natal causes in theoretical explanation. A case is made for estimating stillbirth before 1928 as a ratio of early neonatal death, and for employing perinatal mortality as an historical indicator of female health status. The long-run trend of reproductive mortality (encompassing mature foetal and live born infant death during the first eleven months) reveals a substantial decline in perinatal causes in the first industrial century (1750-1850), implying a major concurrent improvement in the nutritional status of child bearers. Reproductive mortality is a more complete indicator of death in infancy. It offers demographers a means of fracturing the fertility versus mortality dualism and a potential purchase on gender as a demographic variable, while re-opening the case on mortality in the demographic dynamic of the world we have lost.     

Childhood disease and the precautionary demand for children

The childhood disease burden depends on the prevalence of infectious diseases, their case fatalities, and long-term morbidity. We propose a quantity–quality model of fertility choice under uncertainty that emphasizes morbidity and mortality from infectious disease. The fertility response to a decline in child mortality depends on the morbidity effect of the disease, the prevalence rate, and whether the prevalence or case fatality rate declines. Fertility follows mortality and morbidity, but since mortality and morbidity do not always move in the same direction, the fertility response may be dampened or nonmonotonic. Disease-specific evidence from sub-Saharan Africa supports these theoretical predictions.     

The concept and measurement of child dependency: An approach to family formation analysis

Abstract Two distinctions appear crucial in the study of human fertility: (1) aggregate versus individuallevel analysis; and (2) true explanations versus 'demographic explanations', using Stinchcombe's terminology. Social demographers analysing fertility have been accustomed to using fertility measurements derived from aggregative population analyses, and have largely terminated their analytic efforts at the level of a 'demographic explanation'. The failure to arrive at a social analysis of the process of fertility decision-making may in part to be due to this measurement heritage, which may be inappropriate for individual-level analyses. As a first step in the direction of creating measurement suitable for such analyses, fertility decision-making is labelled as family formation decision-making, and this is linked to the concept of child dependency. Measures of child-years-of-dependency (CYD) are proposed for use in family formation analysis. These integrate current quantity and tempo measures, and have greater potential for use at the level ofthe family. They require no additional data beyond fertility histories, are flexible in terms of non-modal family situations (e.g. divorce, infant or child mortality) and may be indicators of criteria used by couples in planning their fertility. Refinements of the basic CYD measures are explored. These include analyses of average versus marginal costs of child-rearing, age gradients of costs and social class differentials in costs. All of these are intended to make CYD measures more useful in individual cost-benefit analyses of child-bearing and child-rearing.     

Effects of Childhood Mortality and Morbidity on the Fertility Transition in sub‐Saharan Africa

Child mortality rates have fallen substantially in developing countries since 1960. The expected fertility decline has followed only weakly in sub‐Saharan Africa compared to other recent and historic demographic transitions. Disease and anthropometric data suggest that morbidity remains prevalent in Africa despite child survival improvements. The uniquely high infectious disease burden among children in Africa reduces population health and diminishes the returns to human capital investment, thwarting the quantity–quality tradeoff for children that typically accompanies the mortality transition. Individual‐level data from the Demographic and Health Surveys are used to show that persistent morbidity has weakened the positive relationship between child mortality and total fertility rates throughout the region, slowing Africa's demographic transition.     

Birth and death in cities in the developing world

City dwellers in Sub-Saharan Africa have increased roughly 600% in the last 35 years. Throughout the developing world, cities have expanded at a rate that has far outpaced rural population growth. Extensive data document lower fertility and mortality rates in cities than in rural regions. But slums, shantytowns, and squatters' settlements proliferate in many large cities. Martin Brockerhoff studies the reproductive and health consequences of urban growth, with an emphasis on maternal and child health. Brockerhoff reports that child mortality rates in large cities are highest among children born to mothers who recently migrated from rural areas or who live in low-quality housing. Children born in large cities have about a 30% higher risk of dying before they reach the age of 5 than those born in smaller cities. Despite this, children born to migrant mothers who have lived in a city for about a year have much better survival chances than children born in rural areas to nonmigrant mothers and children born to migrant mothers before or shortly after migration. Migration in developing countries as a whole has saved millions of children's lives. The apparent benefits experienced in the 1980s may not occur in the future, as cities continue to grow and municipal governments confront an overwhelming need for housing, jobs, and services. Another benefit is that fertility rates in African cities fell by about 1 birth per woman as a result of female migration from villages to towns in the 1980s and early 1990s. There will be an increasing need for donors and governments to concentrate family planning, reproductive health, child survival, and social services in cities, particularly in Sub-Saharan Africa, because there child mortality decline has been unexpectedly slow, overall fertility decline is not yet apparent in most countries, and levels of migration to cities are anticipated to remain high.     

Evaluation of the Olsen Technique For Estimating the Fertility Response to Child Mortality

In a previous issue of this journal, Olsen proposed a technique for quantifying the fertility response to child mortality. To estimate the extent of child replacement, one needs data only on the number of children ever born and the number of child deaths for each woman. The technique involves first running a regression of the number of births on the number of deaths and then correcting the regression coefficient in order to obtain a consistent estimate of replacement. Here we evaluate the performance of the technique by seeing how well it works on a simulated set of reproductive histories for which we know the true extent of replacement. In passing, we derive an extension of the technique to handle the situation in which replacement strategies are heterogeneous. We conclude that the technique performs very well, especially in those cases where the stochastic structure of the data can be diagnosed.     

The Emergence of Lowest‐Low Fertility in Europe During the 1990s

Lowest‐low fertility, defined as a period total fertility rate at or below 1.3, has rapidly spread in Europe during the 1990s. This article traces the emergence of this new phenomenon to the interaction of five factors. First, tempo and compositional distortions reduce the total fertility rate below the associated level of cohort fertility. Second, socioeconomic changes—including increased returns to human capital and high economic uncertainty in early adulthood—have made late childbearing a rational response for individuals and couples. Third, social interaction effects reinforce this behavioral adjustment and contribute to large and persistent postponement in the mean age at birth. Fourth, institutional settings favor an overall low quantum of fertility. Fifth, postponement–quantum interactions amplify the consequences of this institutional setting when combined with ongoing delays of child‐bearing. The article concludes with speculations about future trends in current and prospective lowest‐low‐fertility countries.     

Low fertility due to delay in -- not dearth of -- births

Population Council demographer John Bongaarts and his colleague Griffith Feeney argue that recent concern about a lack of births overlooks the fact that many women in developed countries are simply choosing to bear children later than women used to. So-called birth dearths are often caused by temporary delays in childbearing. The two demographers have designed a new way for demographers to account for the timing, or tempo, of childbearing in estimates of fertility. Their tempo-adjusted total fertility rate (TFR) allows demographers to correct skewed fertility trends, such as those leading to projections of birth dearths. The new measure provides a better indication of women's true propensity to bear children. Standard measures of fertility are distorted by changes in tempo. Such changes occur when large numbers of couples delay or accelerate their initiation of family building. The authors used historical data and theoretical arguments to validate the tempo-adjusted TFR, which improves upon the two common measures of fertility. Flaws in the TFR and the completed fertility rate (CFR) are corrected by Bongaarts and Feeney's new measure. To demonstrate their new tool, they examined the below-replacement fertility seen in recent decades in the US. By the mid-1990s, the TFR in almost every developed country had fallen below the replacement level of 2.1 births/woman, and in Italy, Spain, and Germany it fell below 1.5. If such fertility persists, declining population size, extreme population aging, and financial pressure upon social security systems may result. However, if fertility preferences hold at current levels, the very low fertility rates observed in the developed world will approach 2 children/couple.     

The uncertain lifetime and the timing of human capital investment

I examine the effects of mortality decline on fertility and human capital investment decision of parents taking into account the uncertainty about child survival. I propose a model, where parents decide on their fertility before the uncertainty is realized, but they choose to invest only in human capital of their surviving children. The model implies a positive relationship between mortality and fertility and a negative one between mortality and educational investment. It has been argued elsewhere that as, in reality, most of the mortality decline occurred in infancy, it should not affect the human capital investment decision, which comes later in life. Thus, increased survival chances should not promote growth by raising the human capital investment. This paper argues the contrary and proposes a mechanism where mortality decline at any age before the teen years can promote growth by raising human capital investment regardless of the timing of the educational investment.