Skirbekk's presentation, based on his and co-author Thomas Spoorenberg's latest findings in the article A Concentration of Reproduction to Later Ages? A Worldwide Assessment of Trends in Fertility Timing, that was also featured in N-IUSSP only one day prior to this event, explores the worldwide rise in delayed childbearing. The article states that fertility decline is not correlated with fertility postponement. The shift to later reproduction has major implications for population ageing, maternal child health, and the demand for fertility support services, and it underscores the need for policies that account for both fertility timing and mortality dynamics across diverse regions.
In 2023 more than one third of births were to women aged 30 or older, which is a jump from one fourth in 1990. This increase is driven largely by developed regions such as Europe, North America, Australia/New Zealand, and Eastern Asia, while many developing areas continue to see earlier birth ages.
Although total births fell from 143 million in 1990 to 132 million in 2023, births to women above the age of 30 grew from 36 million to roughly 48 million, and those to women above the age of 35 rose from 14 million to 20 million, now accounting for about 40 % of late births. The shift reflects advanced stages of the demographic transition, where low fertility norms, delayed marriage, extended education, and economic uncertainty push childbearing to later ages. Very late fertility (35+) follows a different trajectory, with its share of late births decreasing from over 50 % in the 1970s to 42 % today, concentrating more in the early 30s.
Historically, late fertility shows a U shaped pattern; high in pre industrial Europe, dipping mid 20th century, and resurging recently. In high fertility regions like sub Saharan Africa, late fertility still makes up 35 45 % of total fertility, whereas in low fertility Europe and Eastern Asia it exceeds 60 % when total fertility is very low. The trend has profound implications for population ageing, maternal child health, and the demand for fertility support services, and its regional variability underscores the need for careful monitoring to inform future demographic forecasts and policy decisions.
Related articles:
Skirbekk, V., Spoorenberg, T. Bringing mortality back into our understanding of fertility change: revisiting the onset of fertility transitions using net reproduction measures. J Pop Research 42, 45 (2025). https://doi.org/10.1007/s12546-025-09394-x
Thomas Spoorenberg and Vegard Skirbekk (2026). Fertility postponement is not a universal correlate of fertility decline. N-IUSSP online magazine. https://www.niussp.org/fertility-and-reproduction/fertility-postponement-is-not-a-universal-correlate-of-fertility-decline/