Fertility Regulation

In the past two centuries the proportion of couples using some form of conscious pregnancy-prevention has risen from close to zero to about two-thirds. In European populations this radical change in behaviour occurred largely between 1870 and 1930 without the benefit of highly effective methods. In Asia, Africa and Latin America, the change took place after 1950 since when the global fertility rate has halved from 5.0 births to 2.5 births per woman. In this chapter we describe the controversies surrounding the idea of birth control and the role of early pioneers such as Margaret Sanger; the advances in contraceptive and abortion technologies; the ways in which family planning has been promoted by many governments, particularly in Asia; trends in use of specific methods; the problems of discontinuation of use; and the incidence of unintended pregnancies and abortions

Birth intervals, postponement, and fertility decline in Africa: a new type of transition?

We investigated birth-interval dynamics in 24 African countries using data from 76 Demographic and Health Surveys conducted since 1986. Controlling for selection bias in the birth-history data using the Brass-Juárez method and regression models produced almost identical results. Birth intervals have lengthened in every country examined. This analysis uncovered a distinctive and previously undocumented pattern of childbearing that is prevalent across sub-Saharan Africa. After allowing for time trends in birth-interval length, the lengthening of birth intervals in almost every country varies little by women's age or parity. Moreover, in several countries, birth intervals are now too long to be explicable by birth spacing contingent on the age of women's youngest child. Rather, women are postponing births for other reasons. These findings offer empirical support for the idea that the fertility transition in sub-Saharan Africa is following a different pattern from that observed elsewhere

Analysis of Difference Approximations to Delay Pseudo-Parabolic Equations

International Conference on Differential and Difference Equations and Applications (ICDDEA) -- MAY 18-22, 2015 -- Mil Acad, Amadora, PORTUGALWOS: 000391876600016This work deals with the one-dimensional initial-boundary Sobolev or pseudo-parabolic problem with delay. For solving this problem numerically, we construct fourth-order difference-differential scheme and obtain the error estimate for its solution. Further, for the time variable, we use the appropriate Runge-Kutta method for the realization of our differential-difference problem. Numerical results supporting the theory are presented

Conflicting Preferences: A Reason Fertility Tends to Be Too High or Too Low

Fertility has often seemed to be too high or too low, relative not only to social and economic goals, but also to reproductive preferences. In developing countries actual fertility has often been higher than desired family size, while in developed societies fertility tends to be below replacement level even though people generally say that they want at least two children. In explanations of fertility extremes, or of the discrepancies between desired and actual fertility, the effect of partners' holding different preferences has tended to be overlooked. Individual preferences expected to lead to replacement-level reproduction may in combination generate substantially higher or lower fertility. In explaining such outcomes, a crucial question is what happens when spousal preferences diverge. Given that personal practices or social norms may systematically favor high or low preferences in the event of disagreement, chance alone will ensure that desired and actual fertility do not coincide. Copyright 2003 by The Population Council, Inc..