A Concentration of Reproduction to Later Ages? A Worldwide Assessment of Trends in Fertility Timing

Abstract This study documents the concentration of childbearing to later reproductive ages, analyzing global patterns of fertility postponement from 1950 to 2040. We study late fertility (ages 30+) and very late fertility (ages 35+) trends at the global, subregional, and national levels using data for all countries and areas of the world since 1950 and historical data for eleven countries dating to 1850. The analysis reveals a significant shift toward late fertility in developed regions only, with fertility increasingly occurring after age 30. Globally, more than one out of three births in 2023 occurs to women aged 30 and above, compared to only one in four in 1990. Historical comparisons indicate similar late fertility patterns in pre‐demographic transition populations and early industrialized societies. The share of childbearing at age 35 among those aged 30 and above is, however, not universally increasing with declining fertility. The study identifies substantial regional disparities in late fertility trends, with some regions maintaining stable late fertility timing despite changes in total fertility levels.