The Decline of Abortion in Spain Over the Last Decade

To analyze how shifts in population composition and variations in the behavior of different sociodemographic groups have changed abortion practices in Spain between 2011 and 2021.

We used data from the Voluntary Terminations of Pregnancies register and Spanish Population and Housing Censuses to examine abortion rates and demographic characteristics of women aged 12-52. We used Poisson regression models and the Oaxaca-Blinder decomposition technique to estimate the contributions of shifts in population structure and variations in behaviors to changes in abortion rates.

We found that 40% of the decline was due to changes in sociodemographic characteristics. Specifically, the relative reduction in the number of younger women in the population and the increase in women's education levels significantly contributed to the decline in abortion rates, while the influx of immigrant women offset some of this reduction. The reduction not explained by these factors was attributed to behavioral changes, with significant reductions in the likelihood of undertaking an abortion also occurring among women under 35, immigrants from non-high-income countries, and lower-educated women.

The study highlights the importance of including changes in the sociodemographic composition of populations in analyses of shifts in abortion rates. It also shows that behavioral changes are not uniform, and that the primary driver of change in abortion rates in Spain is the reduction in abortion rates among the subgroups that had the highest initial rates, leading to a gradual flattening of the differences between women of different ages, education levels, and migratory backgrounds.