Fertility

About: Fertility is a research topic. Over the lifetime, 29988 publications have been published within this topic receiving 681106 citations.

Overview Chapter 5: Determinants of family formation and childbearing during the societal transition in Central and Eastern Europe

Abstract: Societal conditions for early and high rates of childbearing were replaced by conditions generating late and low levels of fertility common in Western countries. Central among factors shaping the latter behaviour (job insecurity unstable partnership relationships expensive housing and profound changes in norms values and attitudes) were the following: increasing proportions of young people were acquiring advanced education a majority of women were gainfully employed yet women were performing most household maintenance and childrearing duties. Two theories prevailed to explain what caused changes in family formation and fertility trends. One argues that the economic and social crises were the principal causes. The other considered the diffusion of western norms values and attitudes as the prime factors of change. Neither reveals the root cause: the replacement of state socialist regimes with economic and political institutions of contemporary capitalism. The extraordinarily low period TFRs around 2000 were the result of low fertility of older women born around 1960 overlapping with low fertility of young women born during the 1970s. (authors)

The relationship between childbearing and transitions from marriage and cohabitation in Britain

Abstract: In this article, we describe a general framework for the analysis of correlated event histories, with an application to a study of partnership transitions and fertility among a cohort of British women. Using a multilevel, multistate competing-risks model, we examine the relationship between prior fertility outcomes (the presence and characteristics of children and current pregnancy) and the dissolution of marital and cohabiting unions and movements from cohabitation to marriage. Using a simultaneous-equations model, we model these partnership transitions jointly with fertility, allowing for correlation between the unobserved woman-level characteristics that affect each process. The analysis is based on the partnership and birth histories that were collected for the 1958 birth cohort (National Child Development Study) aged 16–42. The findings indicate that preschool children have a stabilizing effect on their parents’ partnership, whether married or cohabiting, but the effect is weaker for older children. There is also evidence that although pregnancy precipitates marriage among cohabitors, the odds of marriage decline to prepregnancy levels following a birth.

Obesity leads to higher risk of sperm DNA damage in infertile patients

Abstract: There has been a growing interest over the past few years in the impact of male nutrition on fertility. Infertility has been linked to male overweight or obesity, and conventional semen parameter values seem to be altered in case of high body mass index (BMI). A few studies assessing the impact of BMI on sperm DNA integrity have been published, but they did not lead to a strong consensus. Our objective was to explore further the relationship between sperm DNA integrity and BMI, through a 3-year multicentre study. Three hundred and thirty male partners in subfertile couples were included. Using the terminal uridine nick-end labelling (TUNEL) assay, we observed an increased rate of sperm DNA damage in obese men (odds ratio (95% confidence interval): 2.5 (1.2-5.1)).

The fertility and fecundity of patients with psychoses

Abstract: Objective: Previous research has suggested that patients with schizophrenia have fewer offspring compared to the general population. Reduced fertility in a disorder with a strong genetic component and an apparently stable incidence has implications for models of genetic transmission. There is also a need to obtain contemporary estimates of the prevalence of parenthood among subjects with psychotic disorders in order to inform service planning. The aim of this study was to determine the fertility and fecundity of a representative sample of individuals with psychoses who were in contact with mental health services, and to explore the interactions between age at first diagnosis and fertility. Method: All clients of two community mental health clinics and an extended-care psychiatric hospital were surveyed. Data on diagnosis, age at first diagnosis, and the number and age of offspring were collected. Based on interviews with the proband and chart review, a genogram of the probands' family was drawn that identified sex, age, affected status and the number of offspring for each patient and their siblings. Results: In total, 36% of all patients were parents. Most women with psychoses (59%) were mothers. Patients with psychoses had fewer offspring compared to their unaffected same-sex siblings. This was especially the case for men with non-affective psychoses. Higher levels of fertility were associated with a later age at first diagnosis. Conclusion: The consistent finding of reduced 'reproductive fitness' in those with non-affective psychoses needs to be incorporated in the genetic epidemiology of these disorders. Despite this reduction in fertility and fecundity, many patients with psychoses are parents. Services need to remain mindful of the special needs of these patients.

The coevolution of human fertility and wealth inheritance strategies.

Abstract: Life history theory concerns the scheduling of births and the level of parental investment in each offspring. In most human societies the inheritance of wealth is an important part of parental investment. Patterns of wealth inheritance and other reproductive decisions, such as family size, would be expected to influence each other. Here I present an adaptive model of human reproductive decision-making, using a state-dependent dynamic model. Two decisions made by parents are considered: when to have another baby, and thus the pattern of reproduction through life; and how to allocate resources between children at the end of the parents' life. Optimal decision rules are those that maximize the number of grandchildren. Decisions are assumed to depend on the state of the parent, which is described at any time by two variables: number of living sons, and wealth. The dynamics of the model are based on a traditional African pastoralist system, but it is general enough to approximate to any means of subsistence where an increase in the amount of wealth owned increases the capacity for future production of resources. The model is used to show that, in the unpredictable environment of a traditional pastoralist society, high fertility and a biasing of wealth inheritance to a small number of children are frequently optimal. Most such societies are now undergoing a transition to lower fertility, known as the demographic transition. The effects on fertility and wealth inheritance strategies of reducing mortality risks, reducing the unpredictability of the environment and increasing the costs of raising children are explored. Reducing mortality has little effect on completed family sizes of living children or on the wealth they inherit. Increasing the costs of raising children decreases optimal fertility and increases the inheritance left to each child at each level of wealth, and has the potential to reduce fertility to very low levels. The results offer an explanation for why wealthy families are frequently also those with the smallest number of children in heterogeneous, post-transition societies.