| Abstract: |
After roughly 10 years of decline, the U.S. fertility rate reached a historic
low in 2017. However, aggregate trends in fertility mask substantial
heterogeneity across different demographic groups. Young women and unmarried
women have seen the largest declines in fertility in recent years while women
older than 30 and married women have actually experienced increases. In this
paper, we explore the role of changes in unintended births in explaining
fertility patterns in the U.S. from 1980 to 2017, with an emphasis on the
fertility decline of the last decade. We begin by documenting heterogeneity in
fertility trends across demographic groups, using data from the National
Center for Health Statistics’ Natality Detail Files. We then use data from
the National Survey of Family Growth to describe trends in unintended births
and to estimate a model that will identify the maternal characteristics that
most strongly predict them. Finally, we use this model to predict the
proportion of births in the Natality Detail Files that are unintended. We find
that 35% of the decline in fertility between 2007 and 2016 can be explained by
declines in births that were likely unintended, and that this is driven by
drops in births to young women. |