High fertility is associated with short birth intervals and low fertility is associated with long birth intervals. The length or duration of her birth interval interval from one birth to the next birth or from the last birth to the onset of permanent sterility or marital disruption is determined by three important components, viz.
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Before preserving your articles on this site, please read the following pages: What are the Proximate Determinants of Fertility? The risk rose to about 20 percent at age 35 to 39, and more than 50 percent by age 42". According to the March of Dimes, "At age 25, your risk of having a baby with Down syndrome is 1 in 1, At age 30, your risk is 1 in At age 35, your risk is 1 in At age 40, your risk is 1 in At age 45, your risk is 1 in Some research suggest that increased male age is associated with a decline in semen volume, sperm motility , and sperm morphology.
Decline in male fertility is influenced by many factors, including lifestyle, environment and psychological factors. Some research also suggests increased risks for health problems for children of older fathers, but no clear association has been proven. Australian researchers have found evidence to suggest overweight obesity may cause subtle damage to sperm and prevent a healthy pregnancy.
The American Fertility Society recommends an age limit for sperm donors of 50 years or less,  and many fertility clinics in the United Kingdom will not accept donations from men over 40 or 45 years of age. The French pronatalist movement from — failed to convince French couples they had a patriotic duty to help increase their country's birthrate.
Even the government was reluctant in its support to the movement. It was only between and that the French government became directly and permanently involved in the pronatalist effort. Although the birthrate started to surge in late , the trend was not sustained. Falling birthrate once again became a major concern among demographers and government officials beginning in the s.
From to , fertility fell in the US. There was a marked decline in fertility in the early s, associated with improved contraceptives, greater access to contraceptives and sexuality information and the "first" sexual revolution.
After fertility suddenly started going up again, reaching a new peak in After , fertility started declining rapidly. In the Baby Boom years — , women married earlier and had their babies sooner; the number of children born to mothers after age 35 did not increase. After , new methods of contraception became available, ideal family size fell, from 3 to 2 children.
Couples postponed marriage and first births, and they sharply reduced the number of third and fourth births. Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term. There are many biological causes of infertility, including some that medical intervention can treat.
This article incorporates material from the Citizendium article " Fertility demography ", which is licensed under the Creative Commons Attribution-ShareAlike 3. From Wikipedia, the free encyclopedia.
This article is about fertility in humans. For fertility of other organisms, see fecundity. For fertility of plants and soil, see Soil fertility. For other uses, see Fertile disambiguation. Paternal age effect and Male infertility. Although some early observers saw the declining fertility of the wealthy and the urban as fostering prosperity, by the last quarter of the nineteenth century most emphasized the consequences of differential fertility for the composition of the population.
Women, according to most commentators, were the instigators of fertility decline, and many linked their turn to abortion and contraception to their reassessment of the value of motherhood. The problem was seen to be particularly acute among elite women. When initial attempts to persuade elite women to bear more children failed, attention was turned to persuading others to have fewer, and access to contraception was gradually liberalized. In Western countries the concerns of demographers and policy makers with domestic population composition faded with the widespread low fertility of the s, and the eugenics movement was dealt a serious blow by its association with Nazi Germany in the s and s.
In the s, Western attention turned to population growth rates in developing countries, many of which had until recently been colonies of Western countries. Mortality was declining, but until the s, fertility in most developing countries was relatively high and apparently stable, aside from brief fluctuations associated with wars, famines, and other upheavals.
This stimulated the formation of an international population movement, an alliance of neo-Malthusians, who emphasized the problems consequent on rapid population growth, and birth-controllers, who emphasized the importance of providing women with the means to control their reproduction.
Subsequently, the previous pattern of stable reproduction came to an abrupt halt with the onset of rapid fertility transitions in a majority of countries. Between the early s and the late s , the total fertility rate of the developing world as a whole declined by an estimated 36 percent—from 6. Declines have been most rapid in Asia and Latin America and percent respectively , less rapid but still substantial in the Middle East and North Africa percent , and almost nonexistent in sub-Saharan Africa.
These averages conceal wide variations among countries in the timing of the onset of transitions and their subsequent pace. At one end of the spectrum of experience are a few countries e. At the other extreme are other countries, mostly in sub-Saharan Africa, that have not yet entered the transition.
These remarkable trends in reproductive behavior have been extensively documented in censuses and surveys, and the empirical record is not in dispute Bongaarts and Watkins The causes of these trends, however, are the subject of often-contentious debate. Conventional theories of fertility decline, from the modernization versions dominant in the s and s to neoclassical economic and rational actor versions of recent decades, assume the fundamental importance of socioeconomic change, much as did nineteenth-century theories about industrialization and fertility decline.
Socioeconomic development results in shifts in the costs and benefits of children and hence in the demand for them. As desired family size declines, fertility reduction soon follows with the widespread adoption of birth control, especially when governments make contraceptive services available through family-planning programs. While this broad explanation is widely accepted, analysts vigorously debate the precise variables and processes involved in this chain of causation. These disagreements have been stimulating and fruitful, producing a wide variety of increasingly refined and detailed views that have guided empirical investigations.
Although rises in female marriage age have contributed to the decline in fertility, this decline is largely due to the adoption of new behavior in marriage: More precisely, it is due to the adoption of parity-specific control using modern contraceptives.
In the Third World, fertility decline was closely associated with the use of modern contraceptives. Why did fertility decline? Why did couples start to deliberately limit the number of children they bore? While a comprehensive theory of fertility would account for both the shift from high to low fertility and variations in fertility at each stage of the fertility transition, most of the attempts to understand the social, economic, and cultural influences on fertility have focused on attempts to understand the onset of the fertility transition.
Almost anything that distinguishes traditional from modern societies has been considered relevant to the explanation of the fertility decline Cleland ; see also reviews of fertility determinants by Hirschman ; Kirk ; Mason The most influential theories that have guided demographic research into the determinants of fertility over the last four decades have been those that assume the fundamental importance of economic factor.
Predominant in the s and s was the theory of the demographic transition classic statements are Davis ; Freedman ; Notestein ; Thompson Demographic transition theory is based on the assumption that the means of fertility control used in the early stages of the Western fertility transition were always known. Neoclassical economic theory, and in particular the New Home Economics associated with Gary Becker , provides a translation from macro-level structural changes to the micro-level calculus of parents for a more thorough review, see Pollak and Watkins Empirical examinations driven by these theories gave them some support.
It is, however, also acknowledged that economic factors do not provide a complete explanation. Currently, interesting research focuses on several additions to classical demographic transition theory and to neoclassical economic approaches. Much attention has been devoted to evaluating the role of family-planning programs in the fertility decline in the Third World, where it seems that the methods used initially in the West were either not known or considered too costly in personal terms Knodel et al.
Bongaarts’ aggregate model of the proximate determinants of fertility. Bongaarts (, ) and Bongaarts and Potter () refined Davis and Blake’s framework into 7 important factors, which were termed as the proximate determinants of fertility, to understand .
The proximate determinants of fertility can be classified in two groups, viz., (1) those influencing the length of the reproductive span and (2) those influencing the rate of child-bearing within the reproductive.
Read chapter 5 Proximate Determinants of Fertility: This detailed examination of recent trends in fertility and mortality considers the links between thos. Use this quiz/worksheet as an instrument to cement your awareness of the proximate determinants of fertility. If you want a hard copy assessment.
iv Determinants and Consequences of High Fertility | A Synopsis of the Evidence T his report was prepared by John B. Caster-line (Robert T. Lazarus Professor in Popu-. THE PROXIMATE DETERMINANTS DURING THE FERTILITY TRANSITION Jean-Pierre Guengant* INTRODUCTION Fertility has declined very markedly in the majority of developing countries over the past thirty to.