Long-term effects of childbearing on mortality: Evidence from pre-industrial Sweden

This paper presents an analysis of the impact of childbearing history on later-life mortality for ever-married men and women using historical micro-level data of high quality for southern Sweden. The analysis uses a Cox proportional hazards model, estimating the effects on old-age mortality of number of births and timing of first and last births. By studying the effects of previous childbearing on mortality by sex and social status, we also gain important insights into the mechanisms relating childbearing to mortality in old age. The results show that number of children ever born had a statistically significant negative impact on longevity after age 50 for females but not for males. Analysis by social group shows that only landless women experienced higher mortality from having more children, which seems to indicate that the main explanations are to be found in social or economic conditions specific to females, rather than in the strictly biological or physiological effects of childbearing.     

The effect of number of births on women's mortality: systematic review of the evidence for women who have completed their childbearing

Mortality in women who have completed their childbearing may increase with the number of births experienced because of maternal depletion or a trade-off between reproduction and mortality. We report a systematic review of the evidence on this association. We searched Medline, Embase, Popline, and the Science Citation Index for published and unpublished studies up to September 2003, and the book catalogues of relevant London libraries. Where necessary we also contacted authors for additional information. Mortality declined with increasing numbers of births in twelve historical cohorts, but in eight contemporary cohorts the highest mortality was seen in the nulliparous and in women with more than four births. All effects seen were small and there were few statistically significant results. Studies examining the relationship in other ways (such as by linear trends or by mean number of births by age at death) found inconsistent associations. We discuss methodological, social, and biological factors that may have affected these associations.     

An investigation of the timing pattern of childbearing

This paper reports an investigation of the relation between the number of live births during a woman's reproductive life-cycle and her ages at those births. Four samples of women from the United States and from the Philippines are used. The timing patterns of childbearing in these samples display several striking regularities. In all samples childbearing tends to occur in the centre of the fecund period irrespective of the number of children, so that the mean age at childbearing is essentially independent of final parity. In addition, the timing patterns are symmetric around the mean age at childbearing. Most important of all, the patterns are very alike in the different samples examined, despite large differences between average family size, methods used to regulate fertility, and economic, social, and cultural characteristics in the different populations.     

农村外出妇女的生育意愿分析——基于鄂州、黄石、仙桃三地数据

本文利用2009年2月在鄂州、黄石、仙桃农村外出和未外出育龄妇女的调查数据,通过列联分析和logistic二元回归分析,从四个方面分别考察了外出与未外出育龄妇女生育意愿的关系及其影响因素。结果发现．育龄妇女的意愿子女数主要受其年龄、受教育程度、职业状况等个人特征的影响,外出过的妇女的意愿子女数要显著少于未外出过的妇女,这种差异主要是由于外出妇女与未外出妇女本身的结构差异所引起的,外出本身对育龄妇女的意愿子女数并没有显著作用;在生育目的上,外出与未外出妇女存在显著性差异,外出能弱化传统思想在妇女生育动机中的作用;在意愿生育性别和意愿生育时间这两个方面外出和未外出妇女没有显著性的差异。     

Childbearing and Women's Survival: New Evidence from Rural Bangladesh

Effects of childbearing on women's mortality and the implications of family planning programs in reducing these effects are examined in a 20‐year prospective study of more than 2,000 women in Matlab, Bangladesh. Maternal mortality is defined as a death occurring in the six weeks after childbirth. But childbearing may affect women's survival beyond this brief period. Additional hypotheses considered relate to 1) cumulative exposure to childbearing, whether measured by parity or pace of childbearing, 2) age at first birth, and 3) effects beyond the reproductive ages. The results offer no support to cumulative exposure hypotheses, showing no link between parity or pace of childbearing and mortality risk. Instead, we identify an extended period of heightened mortality risk associated with each birth—the year of the birth and the two subsequent years. Family planning programs, by reducing the number of children and therefore a woman's exposure to extended maternal mortality risk, potentially increase survival. Research is needed to identify and address the specific causes of extended maternal mortality risk so that appropriate ameliorative programs may be developed.     

Negative population growth: how to go about it? (Letter to the editor)

It proves an interesting exercise to try to determine the effects of a national policy of government control developed on the basis of the need to conserve scarce resources, lessen environmental pollution, and to reduce the U.S. population to 1/2 of the 1970 figures within 100 years without increasing the risks of death. Let it additionally be assumed that in order to minimize the required reduction of fertility that there be no net migration. At the end of the reduction process, the stationary state in stable equilibrium might hopefully be achieved. If these are the goals, the process would include 1) reduction of the annual stream of births immediately to the number that would ultimately be required to sustain a population 1/2 as large as the present number and 2) smooth decline of the totals but with constituent age groups shifting drastically as the sharply reduced stream of births spreads upward through the span of life, with those 65 years and older making up 12% of the population. To obtain a fixed annual stream of births from sharply changing numbers of women of childbearing age would require rapid and drastic changes in the rates of childbearing. The same reduced population could be obtained from a system involving less drastic changes in the age composition, but these means would not be positive ones for older individuals. Both fertility and age distribution could move more smoothly if the mortality risks increased or with considerable emigration of the aged. Other means of reducing the population to 1/2 the present size within 100 years would create even more turbulence in the age distribution and rates of childbearing than those just discussed.     

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.     

Baby boomlet for older mothers?

In recent years, a number of celebrities have begun childbearing after age 35. The phenomena of older first-time mothers has received a great deal of attention in the popular press. Are these celebrities indicative of a national trend? Does the increase in fertility portend a reversal of the declines in fertility which have been occurring since the baby boom? The present paper uses central and cumulative birth rates for cohorts of American white women born between 1882 and 1953 to investigate childbearing between ages 35 and 50. While there has been a noticeable upsurge in first birth rates for cohorts in their mid to late 30s in recent years, overall central birth rates for women in their 30s are among the lowest on record, with cumulative birth rates at record low levels. A major reason for this is that these women are having relatively few third and higher order births. These cohorts will need to have a relatively high proportion of births in their older years of childbearing in order to reach replacement level. However, attaining replacement level is unlikely because such a high proportion of women have remained childless at ages 35–40 and a relatively low proportion are having three or more children.     

American families: trends and correlates

Discussion focused on the nature of the roles of the family, a review of the major demographic changes (marriage, cohabitation, nonfamily households, remarriage, fertility, teenage pregnancy, and female employment) affecting the American family in the past decades, and the nature of the impact on women, men, and children. There were four major trends identified: 1) increased proportions of children living in single-parent families due to high rates of divorce and increased childbearing outside of marriage; 2) increased proportions of adults in nontraditional living arrangements; 3) increased female labor force participation during all stages of the life cycle; and 4) decreased proportions of children and increased proportions of older people out of total population due to declining mortality and fertility rates. Family formation arises out of childbearing and childrearing roles, the need for companionship and emotional support, and the opportunities for specialization and trade, and the economies of scale. The costs of family living may include the potential for disagreement, conflict, loss of privacy, and time and money. There were a number of reasons identified for not maintaining traditional families consisting of a married couple with children. The trends were for later age at marriage: 24.4 years in 1992 for women, increased cohabitation (almost 50% cohabiting prior to first marriage in 1985-86), decreased number of married couple households, and increased number of adults in non-family households. The divorce rate has risen over the past 100 years with peaks in the 1970s; the reasons were identified as increased baby boomers and new marriages, increased labor participation of women, and changes in gender roles. The stabilization and slight decline in rates may be due to a natural leveling, the likelihood of greater stability within new marriages, and the aging of the baby boomers. An anticipated increase in divorce rates in the future was also justified. Remarriage rates varied by gender, age at separation/divorce, presence of children, race/ethnicity, and education. Fertility remained stable at 1.8 during the late 1970s and early 1980s and increased slightly to 2.0 in 1989. IN 1990, there were 25% out-of-wedlock births compared to 5% in 1960. About 12% of births in 1989 were to teenagers. There has been an increase in female-headed households, the median income of which in 1992 was $13,012, or 33% of married couple income.     

Childbearing Across Partnerships in Australia,the United States,Norway, and Sweden

This article compares mothers’ experience of having children with more than one partner in two liberal welfare regimes (the United States and Australia) and two social democratic regimes (Sweden and Norway). We use survey-based union and birth histories in Australia and the United States and data from national population registers in Norway and Sweden to estimate the likelihood of experiencing childbearing across partnerships at any point in the childbearing career. We find that births with new partners constitute a substantial proportion of all births in each country we study. Despite quite different arrangements for social welfare, the determinants of childbearing across partnerships are very similar. Women who had their first birth at a very young age or who are less well-educated are most likely to have children with different partners. The educational gradient in childbearing across partnerships is also consistently negative across countries, particularly in contrast to educational gradients in childbearing with the same partner. The risk of childbearing across partnerships increased dramatically in all countries from the 1980s to the 2000s, and educational differences also increased, again, in both liberal and social democratic welfare regimes.     

Sweden faces zero population growth

In this discussion of Sweden as it approaches zero population growth, focus is on the following: population growth in perspective, fertility trends (childbearing concentrated and cohort versus period fertility), marital status (non-marital cohabitation, out-of-wedlock births, and divorce), women's changing status (increasing education and increasing employment), constraints and supports for women's dual role (family allowances and housing), birth control (contraceptive methods and practice and abortion), mortality trends, changing age structure and the elderly (average population age and proportion of elderly and cost of elderly support), international migration (from emigration to immigration and demographic impact of immigration), immigration policy, recent population debate (immigration issues and facing zero population growth). Since 1900 the primary features of Sweden's demographic history are a continuing decline in the birth rate to very low levels -- relieved by some upward movement in the 1940s and 1960s -- and a marked shift in the migration balance from emigration to immigration. It is almost entirely because of immigration that Sweden's population growth rate has not yet turned negative. If Swedish women were to continue to bear children at the rate that all women in the reproductive ages actually did in 1978, each women would end up with an average well below the level necessary to exactly replace each adult in the population leaving migration out, an annual total fertility rate of 2.1 children per woman would have to be sustained for births and deaths to be in balance under the low mortality conditions prevaling in Sweden.     

On Postponement and Birth Intervals

Much of the literature on fertility transition presumes that birth control is practiced either to limit family size or to space births. This article argues that women also use birth control to postpone pregnancy. Postponement is not synonymous with spacing. It arises when women delay their next birth for indefinite periods for reasons unrelated to the age of their youngest child, but without deciding not to have any more children. Postponement has a distinctive impact on the shape of birth‐interval distributions that differs from the impacts of family size limitation, birth spacing, or a mixture of the two behaviors. Some populations, such as that in South Africa, have developed fertility regimes characterized by birth intervals far longer than can be accounted for by birth spacing. Postponement of further childbearing that eventually becomes permanent may be an important driver of the transition to lower fertility in sub‐Saharan Africa.     

The Effect on Fertility of the 2003–2011 War in Iraq

This article provides the first detailed account of recent fertility trends in Iraq, with a particular focus on the changes resulting from the 2003–2011 war and the factors underlying them. The study is based on retrospective birth history data from the 2006 and 2011 Iraq Multiple Indicator Cluster Surveys (I‐MICS). Estimates from the two surveys indicate that total fertility remained stable from 1997 to 2010, at about 4.5 children per woman. However, examination of the age patterns of fertility reveals an abrupt shift in the timing of births, with adolescent fertility rising by over 30 percent soon after the onset of the war. A decomposition analysis shows that the rise in early childbearing is due to an increased prevalence of early marriage among less‐educated women. The prevalence of early marriage and childbearing among women with secondary or higher education is relatively low and has not increased after 2003.     

儿童照料与二孩生育意愿 ——来自上海的证据

本文围绕一项针对上海市育龄女性的生育意愿调查,分别使用二分和有序Logit方法分析儿童照顾对上海市育龄女性的二孩生育意愿的影响。研究发现当育龄女性能够从家庭内和社会中获得更多孩子照料的时间支持时,她们有更高的二孩生育意愿,也会伴有更明确的二孩生育规划;双独家庭能够从父辈获得更多的经济、时间上的帮助,因此他们要比单独家庭和双非家庭更愿意再生一个孩子;居住于上海市城区的女性从某种程度上更易获得孩子的照料资源,有更多的优质教育资源可供选择,因此她们的二孩生育意愿高于居住于郊区的女性。此外,本文通过是否采用了避孕措施对二孩生育的意愿程度做了进一步区分,结果发现当第一个孩子主要是由孩子父母承担照料工作的时候,女性存在二孩生育意愿的程度是最低的,祖辈照料对二孩生育意愿程度的积极影响也明显低于社会性照料,此现象在上海市户籍的女性中体现尤为明显。最后为纠正自选择偏差问题,本文使用倾向值匹配方法(PSM)进一步验证了与首孩性别相比,首孩的抚养成本与接受照料情况显然对二孩生育意愿的影响程度更大。因此,本文认为加大公共托育服务的供给、为育龄女性提供高质量的0-3岁婴幼儿社会照料支持是提高二孩生育意愿的最有效政策。     

The family formation process among U.S. marriage cohorts

The family formation process is viewed as the progression of women through first marriage, first, subsequent, and last births and is examined for differential patterns of timing in 1930–1969 marriage cohorts. Based on the childbearing histories of approximately 17,000 white women once and still married, extracted from the June 1975 Current Population Survey, the study uses a dynamic model to show the varying importance across cohorts of the first birth interval as an important indicator of the total time spent in childbearing, social background effects in differentiating the timing of the first two births, and of prior birth transitions as affecting subsequent ones.     

The effects of breastfeeding and pace of childbearing on mortality at early ages

The effects of the pace of childbearing and breastfeeding practices on infant mortality have rarely been considered together. In this paper, we design and use a set of methodological tools to test a variety of hypotheses postulating the effects of breastfeeding and pace of childbearing on mortality in infancy and early childhood, the mechanisms through which those effects operate, and the contingencies that strengthen or weaken them. The strong effects of both length of breastfeeding and the pace of childbearing on the risks of child death suggest that neither of them exerts an impact on mortality totally mediated by the other. Social and demographic factors (such as age of child, education of mother, and region of residence) also condition the impact of breastfeeding and pace of childbearing on mortality.     

Widowhood,family size,and post-reproductive Mortality: a comparative Analysis of three populations in Nineteenth-Century Europe

Researchers from a number of disciplines have offered competing theories about the effects oJ childbearing on parents 'postreproductive longevity. The "disposable soma theory" argues that investments in somatic maintenance increase longevity but reduce childbearing. "Maternal depletion" models suggest that the rigors of childrearing increase mortality in later years. Other researchers consider continued childbearing a sign of healthy aging and a predictor of future longevity. Empirical studies have produced inconsistent and contradictory results. Our focus is on the experience of widowhood, which has been ignored in previous studies. We hypothesize that the death of a spouse is a stressful event with long-term consequences for health, especially for women with small children. Data are drawn from historical sources in Sweden, Belgium, and the Netherlands from 1766 to 1980. Postreproductive mortality was highest among young widows with larger families in all three samples. Age at last birth had little or no effect. We conclude that raising children under adverse circumstances can have long-lasting, harmful effects on a mother's health.     

Sex preference versus number preference: the case of Korea

The author argues that the effect of sex preference must be disentangled from the effect of number preference in Korea. This study tests--with hazard models--the effect of the number of previous children on the next birth according to the sex composition of previous children. Data were obtained from the 1974 Korean Fertility Survey. This paper also analyzes the timing of childbearing in recent periods in order to determine whether replacement-level fertility is temporary or permanent. The ideal number of children declined from 3.9 children in 1965 to 2.1 in 1991. The age-specific fertility rates for ages 20-24 years declined rapidly during the late 1980s. The fertility rates among women aged 25-29 years and 30-34 years increased during 1985-90. The proportion of fertility among women aged 20-29 years increased from 67.9% in 1975 to 86.6% in 1984. Women born in the late baby boom period of the late 1950s to mid-1960s reached prime reproductive age during the late 1980s and 1990s, but the crude birth rate remained about the same during 1985-92. A higher percentage of women (22.4%) born during 1955-59 remained single in 1990. During 1960-90, the percentage of women aged 20-24 years who were married declined. These trends indicate later age at childbearing and an explanation for the temporary nature of below-replacement fertility in the late 1980s. Korean women did not want to have more than 2 children, and the interval between first and second births increased since 1985. Among pregnancies of parity 2 conceived since 1985, over 90% of women with at least one son ended subsequent pregnancies by abortion compared to only 59% without sons. Hazard models of 1974 data reveal that son preference had an important effect on fertility. Fertility was higher among women with only daughters. Findings suggest that the value of sons must be measured at the societal and not at the individual level.     

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.     

Association of late childbearing with healthy longevity among the oldest-old in China

Statistical analysis of a large and unique longitudinal data-set demonstrates that childbearing after age 35 or 40 is associated with survival and healthy survival among very old Chinese women and men. The association is stronger for women than for men. The estimates are adjusted for a variety of confounding factors: demographic characteristics, family support, social connections, health practices, and health conditions. Further analysis based on an extension of the Fixed-Attributes Dynamics method shows that late childbearing is positively associated with long-term survival and healthy survival from ages 80-85 to 90-95 and 100-105. This association exists among oldest-old women and men, but, again, the effects are substantially stronger for women than for men. We discuss four possible factors that may explain why late childbearing affects healthy longevity at advanced ages: (1) social factors; (2) biological changes caused by late pregnancy and delivery; (3) genetic and other biological characteristics; and (4) selection.