Two leading demographers have a new recommendation for reducing abortion rates worldwide: increase the effective use of contraceptives. Although it may seem like an obvious point, John Bongaarts, vice president of the Policy Research Division at the Population Council in New York, and Charles Westoff of Princeton University actually devised a mathematical model for predicting just how effective the greater use of contraception can be. They report their findings today in the September issue of the Population Council's journal, Studies in Family Planning.

To develop their model, Bongaarts and Westoff analyzed the relationship between abortion rates and a number of influences--including the number of reproductive years per woman, desired fertility rates, a woman's propensity to seek abortion, and the availability and effectiveness of contraception. They calculated that in a population where half of all unintended pregnancies end in abortion, a 10-percentage-point rise in contraceptive prevalence would avert about 0.45 abortion per woman, assuming the form of contraception is at least 95 percent effective.

In fact, experts currently estimate that more than half of the roughly 79 million unintended pregnancies occurring each year end in abortion. Family planning programs in developing countries, where abortions can be particularly dangerous, have helped to lower the number performed, but, conclude Bongaarts and Westoff, "the reach and quality of these [family planning] services are still far from adequate.