The Impact of Contraception and Abortion on Undesired Births: Worldwide Trends before and after the Cairo Consensus

Jonathan Bearak, Guttmacher Insitute
Vladimira Kantorova, United Nations

In this study, we estimate the contributions of contraception and abortion to women’s success in avoiding undesired births, i.e., births that follow from a pregnancy wanted later or unwanted, over the past half-century. To accomplish this, we fit a Bayesian hierarchical model that produces empirical and counterfactual estimates for every five-year period from 1975 to 2024. We compare the empirical trends to counterfactual trends in which contraceptive use and abortion—i.e., the probability that a woman wants and can obtain an abortion following an unintended pregnancy—do not change over time. To measure women’s success in avoiding undesired births, we use conditional unintended birth rates; these relate the number of undesired births to the number of women wanting to avoid pregnancy. Our analysis updates the model developed by the Guttmacher Institute and WHO to estimate worldwide pregnancy trends by intention and outcome. For the number of women who wish to avoid pregnancy, we use the family planning estimates from the United Nations. Our preliminary results indicate that contraception and abortion contributed similarly to trends in Latin America and the Caribbean, abortion contributed more to trends in Asia, and contraception contributed more to trends in Africa.

Keywords: Bayesian methods , Fertility, Family Planning and Contraception, Sexual and Reproductive Health and Rights

See extended abstract.