In societies where large families are desired, the potential unintended pregnancy rate tends to be low. As societies move through the fertility transition, the desired number of children declines along with the number of years needed to reach desired family size. Therefore the number of years during which women are potentially at risk of experiencing an unintended pregnancy increases commensurately. Estimates of the desired number of children range from approximately five in sub-Saharan Africa to two in the Western world.

Spacing preferences also influence the potential unintended pregnancy rate. Women who prefer longer birth intervals are at greater risk of experiencing unintended pregnancies. This consideration is important in the analysis of abortion rates, Bongaarts and Westoff say, because mistimed as well as unwanted pregnancies are potentially subject to termination.

The actual rate of unintended pregnancy depends not only on the potential rate, but also on the extent to which women use contraceptives and on their effectiveness. In theory, if all fecund women who did not wish to become pregnant practiced contraception that is 100 percent effective, there would be no need for abortion. Because not all such women practice contraception, and because methods are less than 100 percent effective, and because even effective methods are sometimes misused, perfect contraceptive use is only an ideal. Contraceptive prevalence varies around the world from less than 10 percent of women of reproductive age in some sub-Saharan countries to around 75 percent in many developed countries.

Use of Abortion Varies Among Regions
Just as contraceptive prevalence varies around the world, so does the use of abortion to terminate pregnancies, the authors note. The proportion of unintended pr
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Contact: Sandra Waldman
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Population Council
12-Sep-2000