Fertility and contraception: The experience of Spanish women born in the first half of the twentieth century

New data based on retrospective interviews with older informants enable us to review the history of contraceptive use among Spanish women over much of the twentieth century. This source is unique because it includes cohorts of women whose reproductive lives took place before, during, and after the baby boom. Traditional contraceptive methods (withdrawal and periodic abstinence) were central to the experience of the first set of women, while the last set made full use of modern as well as some traditional methods. For the first cohorts, traditional methods spearheaded the historic decline in fertility, while among the last set of women modern methods led to a precipitous decline towards the below-replacement fertility that continues in Spain today. There is no evidence that the modest increases in fertility during the baby boom in Spain were the result of a decline in the use of contraception among married women.

Demographic Anxiety and Abortion: Italian Pro-Life Volunteers' and Gynecologists' Perspectives

In this article, we analyze the public debate on fertility decline and abortion in Italy, focusing on demographic anxieties, fueled by conservative demographers and politicians, about the different reproductive behavior of native Italians and migrants. We argue that vitapolitics, a moral regime that defends "life" and condemns abortion, is one of the main mechanisms of reproductive governance in Italy. Drawing on two studies 1) on pro-life volunteers' activism and 2) gynecologists' attitudes to abortion and conscientious objection, we illustrate how vitapolitics shapes the demographic anxieties of these two social actors, who contribute to discipline reproduction on the ground.

The making of 'old eggs': the science of reproductive ageing between fertility and anti-ageing technologies

This article proposes going back in the history of reproductive medicine to shed light on the role of assisted reproductive technology (ART) in the making of 'old eggs'. Focusing on two key technologies - egg donation and cytoplasmic transfer - both of which contributed significantly to the production of scientific knowledge about reproductive ageing, the article suggests that ART can be analysed as 'in-vivo models' playing a pivotal role in the shift from age as a demographic variable to ageing understood in biological terms. It will shed light on the role of ART in locating age in the eggs and producing a cellular understanding of fertility decline. It argues that ART not only offers new means of reconfiguring the biological clock by extending fertility, but also reconfigures the biology of reproductive ageing itself. This becomes both the target and the means for new technological interventions, imaginaries and norms, anchored in women's bodies and a more plastic biology, and thereby illuminates hitherto underexplored aspects of the encounter between the science and technology of reproduction and anti-ageing.

Age at First Marriage and Fertility Decline in Dabat Health and Demographic Surveillance System Site, Northwest Ethiopia: Decomposition Analysis

Background

Fertility decline in Ethiopia has been documented since the 1990s. Amhara National Regional State has recorded the most noticeable fertility decline. However, the specific factors that explain the incipient course of fertility decline in the study area and their relative contributions were not well investigated. Hence, the purpose of this study was to determine contributing factors of fertility decline and to assess variations in fertility that can be attributed to both changes in characteristics and reproductive behaviors of women aged 15-49 years between 2008 and 2014 in Dabat Demographic and Health Surveillance Site, Northwest Ethiopia.

Methods

Cross-sectional censuses were carried out in a Dabat Health and Demographic Surveillance System site in 2008 and 2014. Data for 4,775 and 10,807 women of reproductive age in 2008 and 2014 were used for the analysis. A Poisson regression model was employed to assess the trends of determinants of fertility, and multivariate decomposition analysis was applied to evaluate observed changes in fertility using data from two consecutive cross-sectional censuses of Dabat HDSS.

Results

Findings indicated that there was a reduction of an average 640.69 births per 1,000 women of reproductive age during 2014 compared to 2008 in the surveillance site (95% CI=-669.5 to -582.4). This overall change in fertility was attributed to both the changing characteristics of women (76%) (95% CI=-524.74 to -453.13) and their reproductive behavior (24%) (95% CI=-224.36 to -79.14). Drivers of the recent fertility decline were increased age at first marriage, a decreased proportion of currently married women, shift in women's birth to later age, and a higher women's educational status.

Conclusion

This study indicated that the overall reduction in fertility was attributed to both changing characteristics of women and their reproductive behavior. Major contributors to the changes in fertility were postponing women's first marriage to a later age and changes in the proportion of currently married women over the study period. Encouraging women to complete at least secondary education is important to increase the age at first marriage and birth, which will in turn accelerate the current fertility transition.

Generating and capitalizing on the demographic dividend potential in sub-Saharan Africa: a conceptual framework from a systematic literature review

Background: Africa will double its population by 2050 and more than half will be below age 25. The continent has a unique opportunity to boost its socioeconomic welfare. This systematic literature review aims to develop a conceptual framework that identifies policies and programs that have provided a favorable environment for generating and harnessing a demographic dividend. This framework can facilitate sub-Saharan African countries' understanding of needed actions to accelerate their demographic transition and capitalize on their demographic dividend potential. Methods: The search strategy was structured around three concepts: economic development, fertility, and sub-Saharan Africa. Databases used included PubMed and EconLit. An inductive approach was employed to expand the reference base further. Data were extracted using literature records following a checklist of items to include when reporting a systematic review suggested in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Results: The final review consisted of 78 peer-reviewed articles, ten reports from the gray literature, and one book. Data were categorized according to relevant demographic dividend typology: pre-dividend and early-dividend. The results from the literature review were synthesized into a framework consisting of five sectors for pre-dividend countries, namely 1) Governance and Economic Institutions, 2) Family Planning, 3) Maternal and Child Health, 4) Education, and 5) Women's Empowerment. An additional sector, 6) Labor Market, is added for early-dividend countries. These sectors must work together to attain a demographic dividend. Conclusions: A country's demographic transition stage must guide policy and programs. Most sub-Saharan African countries have prioritized job creation and employment for youth, yet their efforts to secure a productive labor market require preliminary and complementary investments in governance, family planning, maternal and child health, education, and women's empowerment. Creating a favorable policy environment for generating and capitalizing on a demographic dividend can support their stated goals for development.

Prevalence of chromosome anomalies in a deer farm with fertility decline in Malaysia

BACKGROUND

A number of factors are known to reduce fertility rate in animals and one of the important categories of such factors is chromosome anomalies. They can occur with or without causing phenotypic abnormalities on animals; in some cases, they may directly affect meiosis, gametogenesis and the viability of conceptus. In many instances, balanced structural rearrangements can be transmitted to offspring, affecting fertility in subsequent generations.

AIM

This work investigated the occurrence of chromosome aberrations in Rusa timorensis, Rusa unicolor and Axis axis raised in a nucleus deer farm in Malaysia with a history of declining fertility of unknown origin.

MATERIALS & METHODS

Blood samples were collected from 60 animals through venipuncture, cultured for 72 h and arrested at metaphase. SmartType® and Ideokar® software were used to karyotype the chromosomes.

RESULTS

We found 15 out of the 60 animals screened from both sexes harbor some form of chromosome aberration. Chromosomal aberrations exist at the rate of 25% and may not be unconnected with the observed reduced fertility on the farm. Further investigations should be carried out, especially on the offspring of the studied animals to transmission of these aberrations. The animals that are confirmed to transmit the chromosomal aberrations should be culled to arrest the propagation of their abnormalities.

Dairy cow reproduction under the influence of heat stress

Dairy farming is vulnerable to global warming and climate change. Improving and maintaining conception rates (CRs) have a paramount importance for the profitability of any dairy enterprise. There is an antagonistic relationship between fertility and milk yield, and intensive selection for milk yield has severely deteriorated reproductive efficiency. Irrespective of geography and husbandry, modern dairy cows experience heat stress (HS) effects leading to fertility declines, but it worsens in tropical climates. The threshold of HS experience among modern dairy cow has lowered, leading to decreased thermal comfort zone. Studies show that this threshold is lower for fertility than for lactation. HS abatement and robustness response to lactation yield lead to negative energy balance, and cow's reproductive requirements remain unfulfilled. The adverse effects of HS commence from developing oocyte throughout later stages and its fertilization competence; the oestrus cycle and oestrus behaviour; the embryo development and implantation; on uterine environment; and even extend towards foetal calf. Even cows can become acyclic under the influence of HS. These harmful effects of HS arise due to hyperthermia, oxidative stress and physiological modifications in the body of dairy cows. Proper assessment of HS and efficient cooling of dairy animals irrespective of their stage of life at farm is the immediate strategy to reduce fertility declines. Other long- and short-term mitigation strategies to reduce fertility declines during HS include feeding care, reducing disease and mastitis rates, using semen from cooled bulls, timed artificial inseminations (AI), allied hormonal interventions and use of embryo transfer technology. Ultimate long-term solution should be well-planned breeding for fertility improvement and HS tolerance.

Elective egg freezing without medical indications

The aim of this review is to provide current knowledge on fertility preservation for non-medical reasons in women willing to postpone childbearing. The topic is highly debatable, starting from disagreement about its terminology, the number of eggs necessary to predict chances of success, and the safety and socio/ethical point of view. Cost analysis and discrepancies among countries' recommendations and regulations are described to confirm the controversies and unsolved issues around this very interesting topic. Finally, an overview on the returning rate of women among "egg bankers" and reasons behind their decisions are illustrated.

[Exposure of man to metal trace elements and alteration of sperm parameters: study conducted in the mining areas of Haut-Katanga in the Democratic Republic of Congo]

Introduction

L'exposition à l'arsenic et au cadmium entraine des effets néfastes importants. L'objectif de cette étude est de déterminer les concentrations urinaires en arsenic et en cadmium chez les hommes et d'analyser leur profil en rapport avec les éléments du spermogramme.

Méthodes

Il s'agit d'une étude analytique exposés-non exposés où les hommes exposés ont été recrutés dans une zone minière du Haut-Katanga, en RDC et les hommes non-exposés dans une zone loin de toute activité minière.

Résultats

Nos résultats montrent que 48% des sujets exposés ont un pH du sperme en dessous de la valeur seuil de 7,2 contre seulement 16% des sujets non-exposés. Le risque d'abaissement du pH en deçà des normes étant de plus de 4 fois supérieur (OR=4,85 [1,9-12,39]) chez les exposés. La différence est statistiquement significative entre les moyennes du nombre global des spermatozoides à l'avantage des sujets non-exposés et celles des spermatozoides anormaux beaucoup plus chez les sujets exposés. On note une dégradation plus rapide de la mobilité des spermatozoides chez les sujets exposés. Par ailleurs, 44% des hommes exposés ont une concentration urinaire en arsenic > 20 µg/l contre 8% des sujets non-exposés, le risque d'accumulation excessive d'arsenic est neuf fois plus élevé chez les hommes exposés que chez ceux non exposées (OR=9,04 [2,82-28,96]). Soixante pourcents des hommes exposés ont une concentration urinaire en cadmium ≥ 0,5 µg/ml contre 38% des sujets non-exposés avec un Odd Ratio de 2,45 [1,1-5,47], traduisant un risque d'accumulation excessive de cadmium chez les hommes exposés. D'autre part, on constate chez les hommes exposés que les fortes concentrations urinaires en arsenic et en cadmium entrainent une dégradation proportionnelle des éléments du spermogramme.

Conclusion

Le présent travail montre bien d'une part de fortes concentrations urinaires d'arsenic et de cadmium et d'autre part l'altération plus rapide et plus sévère des éléments du spermogramme chez les hommes vivant en zone minière, suggérant une baisse de la fertilité masculine qui mérite d'être davantage documentée dans les travaux futurs.

Mortality, fertility, and economic development: An analysis of 201 countries from 1960 to 2015

Background: The efficient utilization of the economic opportunities effected by rapid reductions in fertility and mortality is known as the demographic dividend. In this paper, our objectives are to (1) estimate the contribution of fertility and mortality decline during the period 1960-2015 to demographic dividend due to change in age structure, and (2) assess the economic consequences of population age structure change.

Methods: Employing the cohort component method, we performed population projections with different scenarios of changes in mortality and fertility between 1960 and 2015 in 201 countries. We specifically focused on low- and middle-income countries in Asia, Latin America and the Caribbean (LAC), Northern Africa, and sub-Sahara Africa (SSA)

Results: The child dependency ratio, defined as the number of children (0-14 years) per 100 working age population (15-64 years), would be 54 higher than the observed level in 2015 in both Asia and LAC, had fertility not declined. That means that every 100 working age population would need to support an additional 54 children. Due to the less substantial fertility decline, child dependency ratio would only be 16 higher if there were no fertility decline in SSA. Global GDP (constant 2011 international $) would be $19,016 billion less than the actual level in 2015 had the fertility decline during 1960-2015 not occurred, while the respective regional decreases are $12,390 billion in Asia, $1,985 billion in LAC, $484 billion in Northern Africa, and $321 billion in SSA.

Conclusions: SSA countries may accelerate the catch-up process in reducing fertility by investing more in family planning programs. This will lead to a more favorable dependency ratio and consequently facilitate a demographic dividend opportunity in SSA, which, if properly utilized, will spur economic development for the coming decades.

Modelling period fertility: Schooling and intervals following a birth in Eastern Africa

We describe a regression-based approach to the modelling of age-, order-, and duration-specific period fertility, using retrospective survey data. The approach produces results that are free of selection biases and can be used to study differential fertility. It is applied to Demographic and Health Survey data for Ethiopia, Kenya, Tanzania, and Zimbabwe to investigate differential trends in fertility by education. Parity progression fell and the intervals following each birth lengthened between the 1970s and 2000s in all four countries. Fertility fell most among women with secondary education. In contrast to other world regions, postponement of successive births for extended periods accounted for much of the initial drop in fertility in these African countries. However, family size limitation by women with secondary education in Ethiopia and Kenya and longer birth spacing in Zimbabwe also played significant roles. Thus, birth control is being adopted in Eastern Africa in response to diverse changes in fertility preferences.

The cultural evolution of fertility decline

Cultural evolutionists have long been interested in the problem of why fertility declines as populations develop. By outlining plausible mechanistic links between individual decision-making, information flow in populations and competition between groups, models of cultural evolution offer a novel and powerful approach for integrating multiple levels of explanation of fertility transitions. However, only a modest number of models have been published. Their assumptions often differ from those in other evolutionary approaches to social behaviour, but their empirical predictions are often similar. Here I offer the first overview of cultural evolutionary research on demographic transition, critically compare it with approaches taken by other evolutionary researchers, identify gaps and overlaps, and highlight parallel debates in demography. I suggest that researchers divide their labour between three distinct phases of fertility decline--the origin, spread and maintenance of low fertility--each of which may be driven by different causal processes, at different scales, requiring different theoretical and empirical tools. A comparative, multi-level and mechanistic framework is essential for elucidating both the evolved aspects of our psychology that govern reproductive decision-making, and the social, ecological and cultural contingencies that precipitate and sustain fertility decline.

Pathways from education to fertility decline: a multi-site comparative study

Women's education has emerged as a central predictor of fertility decline, but the many ways that education affects fertility have not been subject to detailed comparative investigation. Taking an evolutionary biosocial approach, we use structural equation modelling to examine potential pathways between education and fertility including: infant/child mortality, women's participation in the labour market, husband's education, social network influences, and contraceptive use or knowledge across three very different contexts: Matlab, Bangladesh; San Borja, Bolivia; and rural Poland. Using a comparable set of variables, we show that the pathways by which education affects fertility differ in important ways, yet also show key similarities. For example, we find that across all three contexts, education is associated with delayed age at first birth via increasing women's labour-force participation, but this pathway only influences fertility in rural Poland. In Matlab and San Borja, education is associated with lower local childhood mortality, which influences fertility, but this pathway is not important in rural Poland. Similarities across sites suggest that there are common elements in how education drives demographic transitions cross-culturally, but the differences suggest that local socioecologies also play an important role in the relationship between education and fertility decline.

Fertility decline and the changing dynamics of wealth, status and inequality

In the course of demographic transitions (DTs), two large-scale trends become apparent: (i) the broadly positive association between wealth, status and fertility tends to reverse, and (ii) wealth inequalities increase and then temporarily decrease. We argue that these two broad patterns are linked, through a diversification of reproductive strategies that subsequently converge as populations consume more, become less self-sufficient and increasingly depend on education as a route to socio-economic status. We examine these links using data from 22 mid-transition communities in rural Poland. We identify changing relationships between fertility and multiple measures of wealth, status and inequality. Wealth and status generally have opposing effects on fertility, but these associations vary by community. Where farming remains a viable livelihood, reproductive strategies typical of both pre- and post-DT populations coexist. Fertility is lower and less variable in communities with lower wealth inequality, and macro-level patterns in inequality are generally reproduced at the community level. Our results provide a detailed insight into the changing dynamics of wealth, status and inequality that accompany DTs at the community level where peoples' social and economic interactions typically take place. We find no evidence to suggest that women with the most educational capital gain wealth advantages from reducing fertility, nor that higher educational capital delays the onset of childbearing in this population. Rather, these patterns reflect changing reproductive preferences during a period of profound economic and social change, with implications for our understanding of reproductive and socio-economic inequalities in transitioning populations.

Having fewer children makes it possible to educate them all: an ethnographic study of fertility decline in north-western Tigray, Ethiopia

Education is presumed to play a decisive role in decreasing fertility rates. This article is about the role of education and other factors in fertility decline in the context of current Ethiopian policies on population and sustainable development, based on an ethnographic study of women's agency and girls' pursuit of education in one semi-urban and one rural area in north-western Tigray, in northern Ethiopia. Long-term environmental insecurity and scarcity of arable land for the younger generation in this area serve as important background. Another central issue in the study was the religious conditioning of women's choices, which stood out most clearly in the case of contraceptive use. The research consisted of in-depth, semi-structured interviews in 2008 with 25 purposively selected women from three generations, based on their life histories, linked with participatory observation and extended informal dialogue with women at different points during 2008-12. A smaller household survey with 170 women and a task-based, education survey with 200 female and male students were also conducted in 2009. In those cases where women's contestations of the authority of the Orthodox Christian priests concurred with current Ethiopian policies on fertility decline, this was based on what women defined as their own authority in reproductive matters linked with flexible adaptation to their life-situations.

Fertility Decline, Gender Composition of Families, and Expectations of Old Age Support

Recent fertility declines in non-Western countries may have the potential to transform gender systems. One pathway for such transformations is the creation of substantial proportions of families with children of only one gender. Such families, particularly those with only daughters, may facilitate greater symmetry between sons and daughters. This article explores whether such shifts may influence gendered expectations of old age support. In keeping with patriarchal family systems, old age support is customarily provided by sons, but not daughters, in India. Using data from the 2005 Indian Human Development Survey, I find that women with sons overwhelmingly expect old age support from a son. By contrast, women with only daughters largely expect support from a daughter or a source besides a child. These findings suggest that fertility decline may place demographic pressure on gendered patterns of old age support and the gender system more broadly.

Social network- and community-level influences on contraceptive use: evidence from rural Poland

The diffusion of 'modern' contraceptives-as a proxy for the spread of low-fertility norms-has long interested researchers wishing to understand global fertility decline. A fundamental question is how local cultural norms and other people's behaviour influence the probability of contraceptive use, independent of women's socioeconomic and life-history characteristics. However, few studies have combined data at individual, social network and community levels to simultaneously capture multiple levels of influence. Fewer still have tested if the same predictors matter for different contraceptive types. Here, we use new data from 22 high-fertility communities in Poland to compare predictors of the use of (i) any contraceptives-a proxy for the decision to control fertility-with those of (ii) 'artificial' contraceptives-a subset of more culturally taboo methods. We find that the contraceptive behaviour of friends and family is more influential than are women's own characteristics and that community level characteristics additionally influence contraceptive use. Highly educated neighbours accelerate women's contraceptive use overall, but not their artificial method use. Highly religious neighbours slow women's artificial method use, but not their contraceptive use overall. Our results highlight different dimensions of sociocultural influence on contraceptive diffusion and suggest that these may be more influential than are individual characteristics. A comparative multilevel framework is needed to understand these dynamics.

New Zealand University students' knowledge of fertility decline in women via natural pregnancy and assisted reproductive technologies

Female fertility declines with age. University students are the group of people most likely to postpone parenthood, yet several international studies have shown that they overestimate their fertility. We designed a questionnaire based on a previous study in Israel, where university students were asked to answer questions related to their awareness of fertility decline in spontaneous and in vitro fertilisation (IVF) pregnancies, and methods they considered would prolong their reproductive lifespan. Our study has shown that New Zealand University students overestimated the rates of pregnancy for both spontaneous natural and IVF pregnancies. Students are mainly aware of the availability of assisted reproductive technologies (ARTs), but overestimate their effectiveness. Few students mentioned non-medical or well-being initiatives as measures to prolong parenthood. It is important that university students are aware of the rate of fertility decline in women, as although ARTs can be effective at times, they are not a guaranteed solution to an ageing woman's fertility. New Zealand University students, like other cohorts, overestimated the chances of a woman getting pregnant and predicted the fertility decline to occur much later than it does in reality.

Community-level education accelerates the cultural evolution of fertility decline

Explaining why fertility declines as populations modernize is a profound theoretical challenge. It remains unclear whether the fundamental drivers are economic or cultural in nature. Cultural evolutionary theory suggests that community-level characteristics, for example average education, can alter how low-fertility preferences are transmitted and adopted. These assumptions have not been empirically tested. Here, we show that community-level education accelerates fertility decline in a way that is neither predicted by individual characteristics, nor by the level of economic modernization in a population. In 22 high-fertility communities in Poland, fertility converged on a smaller family size as average education in the community increased-indeed community-level education had a larger impact on fertility decline than did individual education. This convergence was not driven by educational levels being more homogeneous, but by less educated women having fewer children than expected, and more highly educated social networks, when living among more highly educated neighbours. The average level of education in a community may influence the social partners women interact with, both within and beyond their immediate social environments, altering the reproductive norms they are exposed to. Given a critical mass of highly educated women, less educated neighbours may adopt their reproductive behaviour, accelerating the pace of demographic transition. Individual characteristics alone cannot capture these dynamics and studies relying solely on them may systematically underestimate the importance of cultural transmission in driving fertility declines. Our results are inconsistent with a purely individualistic, rational-actor model of fertility decline and suggest that optimization of reproduction is partly driven by cultural dynamics beyond the individual.

Parenthood, child-rearing and fertility in England, 1850-1914

Fertility declines across Europe and the Anglo-world have been explained as the result of reversals of intergenerational flows of wealth. According to this theory, the child was transformed from an economically-useful household asset to an emotionally-valued parental burden. This article is based on a comparative study of changing understandings of parenthood in three provincial English localities between 1850 and 1914. It works from the premise that in order to make sense of reproductive behaviour, it is essential to examine the meanings that men and women attached to childlessness, child-rearing and parenthood. It is argued that there was not a universal shift that made children into burdens. New understandings of the duties of parenthood did develop, but these were founded on class-, gender- and place-specific interpretations. These encouraged a minority of fathers and mothers to believe that together they had the capacity to improve the lives of their sons and daughters in pioneering ways. Given that husbands and wives had distinct motives for avoiding rearing many children and that the discussion of reproduction was shrouded in silence, the dissemination and use of new ideals of family was crucial in enabling birth control to be thought about respectably within marriage.

Convergence in fertility of South Africans and Mozambicans in rural South Africa, 1993-2009

Background

Although there are significant numbers of people displaced by war in Africa, very little is known about long-term changes in the fertility of refugees. Refugees of the Mozambican civil war (1977–1992) settled in many neighbouring countries, including South Africa. A large number of Mozambican refugees settled within the Agincourt sub-district, underpinned by a Health and Socio-demographic Surveillance Site (AHDSS), established in 1992, and have remained there. The AHDSS data provide a unique opportunity to study changes in fertility over time and the role that the fertility of self-settled refugee populations plays in the overall fertility level of the host community, a highly relevant factor in many areas of sub-Saharan Africa.

Objectives

To examine the change in fertility of former Mozambican self-settled refugees over a period of 16 years and to compare the overall fertility and fertility patterns of Mozambicans to host South Africans.

Methods

Prospective data from the AHDSS on births from 1993 to 2009 were used to compare fertility trends and patterns and to examine socio-economic factors that may be associated with fertility change.

Results

There has been a sharp decline in fertility in the Mozambican population and convergence in fertility patterns of Mozambican and local South African women. The convergence of fertility patterns coincides with a convergence in other socio-economic factors.

Conclusion

The fertility of Mozambicans has decreased significantly and Mozambicans are adopting the childbearing patterns of South African women. The decline in Mozambican fertility has occurred alongside socio-economic gains. There remains, however, high unemployment and endemic poverty in the area and fertility is not likely to decrease further without increased delivery of family planning to adolescents and increased education and job opportunities for women.

Measurement of and trends in unintended birth in Bangladesh, 1983-2000

Bangladesh has experienced a rapid decline in fertility in the past several decades, facilitated by proactive population policies, provision of contraceptives, and broader societal shifts, encouraging smaller families and use of contraceptive to achieve revised childbearing norms. This paper presents 18 years of data from the Sample Registration System, a demographic surveillance system operated by the Maternal and Child Health-Family Planning Extension Project in six study areas in Bangladesh. Prospective measurements of women's fertility preferences were used for classifying nearly 25,000 birth outcomes from 1983 to 2000 as intended, unintended, or 'up to God/Allah'. Over the 18-year period, the level of unintended births varied from 22% to 38%, with the lowest levels in the mid-1990s. Fatalistic responses declined significantly from 25% in the mid-1980s to 1% by the late 1990s. Results of the comparison of two geographic areas of Bangladesh indicate differential declines in the levels of unintended pregnancies over the study period. Prospective measurements of unintended pregnancies were 2-3 times the magnitude indicated by retrospective estimates of unwanted births from the demographic and health surveys conducted during the study period. This unique dataset provides a rare opportunity to visualize the vast changes in fertility preferences and unintended births in Bangladesh from 1983 to 2000. Significant declines in fatalistic responses reflect broader social changes that occurred in Bangladesh to facilitate the fertility decline and contraceptive uptake. The drastic differences between prospective and retrospective measurements of fertility preferences highlight the importance of considering the strengths and limitations of each method when attempting to estimate the true level of unintended pregnancies and births in a population.

Fertility decline in rural China: a comparative analysis

Many models have been proposed to explain both the rapidity of China's fertility decline after the 1960s and the differential timing of the decline in different places. In particular, scholars argue over whether deliberate policies of fertility control, institutional changes, or general modernization factors contribute most to changes in fertility behavior. Here the authors adopt an ethnographically grounded behavioral-institutional approach to analyze qualitative and quantitative data from three different rural settings: Xiaoshan County in Zhejiang (East China), Ci County in Hebei, (North China), and Yingde County in Guangdong (South China). The authors show that no one set of factors explain differential timing by a combination of differences in social-cultural environments (e.g. spread of education, reproductive ideologies, and gender relations) and politico-economic conditions (e.g. economic development, birth planning campaigns, and collective systems of labor organization) during the early phases of the fertility decline.

Do women stop early? Similarities in fertility decline in humans and chimpanzees

Two kinds of evidence suggest that female fertility may end at an earlier age in modern people than in ancestral populations or in our closest living relatives, chimpanzees. We investigate both to see whether fertility schedules or ovarian follicle counts falsify the alternative hypothesis that the age of terminal fertility changed little in the human lineage while greater longevity evolved due to grandmother effects. We use 19th century Utah women to represent non-contracepting humans, and compare their fertility by age with published records for wild chimpanzees. Then we revisit published counts of ovarian follicular stocks in both species. Results show wide individual variation in age at last birth and oocyte stocks in both humans and chimpanzees. This heterogeneity, combined with interspecific differences in adult mortality, has large and opposing effects on fertility schedules. Neither realized fertility nor rates of follicular atresia stand as evidence against the hypothesis that ages at last birth changed little while greater longevity evolved in our lineage.

Low Fertility at the Turn of the Twenty-First Century

In the past few decades, demographic concerns have shifted from rapid population growth fueled by high fertility to concerns of population decline produced by very low, sub-replacement fertility levels. Once considered a problem unique to Europe or developed nations, concerns now center on the global spread of low fertility. Nearly half of the world's population now lives in countries with fertility at or below replacement levels. Further, by the mid-twenty-first century three of four countries now described as developing are projected to reach or slip below replacement fertility. We review the research on low fertility through the predominant frameworks and theories used to explain it. These explanations range from decomposition and proximate determinant frameworks to grand theories on the fundamental causes underlying the pervasiveness and spread of low fertility. We focus on the ability of theory to situate previous and future findings and conclude with directions for furthur research.