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Results for “Low Fertility Population”

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At least 19 recordsLinked to original sources
PubMed1993

Crossovers that link populations with the same vital rates.

"In this paper, we consider crossovers of demographic density distributions from...populations that have the same fertility and mortality rates. We focus on observed populations and their associated stationary and stable models, and on proportional distributions of persons, births, deaths and reproductive values.... Three different populations were selected to represent a range of demographic behavior. Those populations are Japan 1963, a low mortality, low fertility population; Togo 1961, a high mortality, high fertility population; and the United States 1919-1921, a population whose fertility and mortality are intermediate."

Africa↗
PubMed1994

Global patterns of seasonal variation in human fertility.

Pronounced and persistent seasonal patterns in fertility are observed in virtually all human populations. This paper presents evidence on these seasonal patterns. We note that the most pronounced seasonal patterns are in the southern United States, where births decline substantially in April and May, and in northern Europe, where births increase substantially in March and April. Although seasonal variations in fertility were more pronounced in earlier agricultural populations, we show that seasonality has increased in this century in some high income, low fertility populations such as Sweden. We use data on monthly temperature to analyze the potential role of temperature in explaining seasonal patterns. We find strong evidence that summer heat plays an important role in explaining the July-August trough in conceptions in the southern United States. We find little evidence, however, that temperature plays any role in explaining the pronounced June-July peak in conceptions in Sweden. Temperature also appears to be relatively unimportant in several other populations with substantial seasonal variations in births, suggesting that other factors play an important role in birth seasonality.

Birth Rate↗
PubMed1983

Patterns of life events derived from demographic rates and social norms.

"A simulation programme is described which constructs whole life courses from sequences of birth, entering into and dissolution of marriage, fertility and death. Data are derived from probabilities of these events based on demographic rates and social rules (the SOCSIM programme); descriptions of lives are obtained from a post-processor. The simulation is applied to two contrasting populations [the United States and Madagascar] to show the relative influence of vital rates and divorce rules on lives in a high mortality-high fertility and low mortality-low fertility population."

Africa↗
PubMed1988

Limits and possibilities relating to family structure and care of the aged in populations with unprecedentedly low fertility.

"While demographic conditions need not necessarily be prime determinants of the quality of people's lives, there can be no doubt that they determine the limits of that quality. This paper discusses these limits with reference to family and kinship structure, and particularly the wellbeing of the elderly, in European populations (both in Europe and overseas) currently subject to especially high rates of ageing as a result, primarily, of unprecedentedly low fertility. Emphasis is placed on the fact of heterogeneity within populations, the great variety of possible social responses to human needs and demographic conditions, and the fact that the future is fraught with uncertainty, despite the degree of ineluctability associated with certain demographic processes." Comparative data for Australia are presented.

Adult↗
PubMed1992

Immigrant's ages and the structure of stationary populations with below-replacement fertility.

A sustained regime of low fertility plus immigration yields an unusual kind of stationary population. The author demonstrates that all stationary populations have a common structure, and that the familiar replacement-level fertility population is the youngest among the many stationary populations corresponding to a particular life table. This finding has important consequences for policy because although fertility increase and immigration are equally effective at halting population decline, immigration is inferior as a means of rejuvenating low-fertility populations. In fact, an immigration-based policy could make a low-fertility population older rather than younger. The paper includes examples using U.S. and West German vital rates.

Adolescent↗
PubMed2003

Impact of low birthweight on subsequent fertility: population-based register study.

Adverse birth outcomes may influence a family's wish for additional children. We investigated the influence of low birthweight in live births on subsequent fertility, and estimated secular trends of such an effect in a population-based cohort study of births arranged in consecutive sibship records in the Medical Birth Registry of Norway. We included births of order one to seven to all 587 785 mothers in Norway who had a first singleton birth in 1967-91. Associations between birthweight in 1 158 072 surviving index births of order one to six, 1967-91, and subsequent fertility (probability of another birth), 1967-97, were estimated as fertility ratios in Cox regression analysis. Giving birth to a live infant weighing < 3000 g had a negative effect on subsequent fertility, increasingly strong for decreasing birthweight. Low birthweight (<2500 g) was associated with a fertility ratio of 0.88 [95% confidence interval 0.87, 0.89]. This negative impact was stronger if the mother had also given birth to surviving children of low birthweight previously, particularly if combined with caesarean section in the most recent birth. The negative fertility effect of low birthweight grew slightly stronger between 1967 and approximately 1980, according to year of first birth. This trend paralleled reduced population fertility in the same period. The moderate negative impact of giving birth to a live infant of low birthweight on subsequent fertility could result from the combination of reduced wish for additional children and biological subfertility.

Female↗
PubMed1990

Time and trajectory of convergence to population stationarity with immigration and low fertility.

"Recent research aimed at extending classical stable population theory to include immigration has shown that a stationary population is the long-term equilibrium outcome if, starting from any initial configuration, a population is projected forward under conditions of constant below-replacement fertility, constant mortality, and a constant annual number of immigrants whose age-sex composition is also fixed. This paper addresses two related questions: (1) What path does the projected population follow on its way to a long-term stationary population equilibrium? and (2) How long does it take for a stationary population to be achieved? To answer these questions a formal theory of population dynamics in the below replacement case is developed and then illustrated with a projection of the 1980 U.S. population."

Americas↗