Author: Dr Ioannis Gryparis, Medical Director South Europe, NOW-fertility
Accurate assessments of current and future fertility are crucial for planning and preparing for the social, economic, environmental, and geopolitical challenges that come with changing population age structures.
As reported in The Lancet this month, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides comprehensive demographic assessments of fertility indicators from 1950 to 2021 at global, regional, and national levels. During this period, the global Total Fertility Rate (TFR) decreased by more than half, from 4.84 to 2.23. Demographic data in the 5 years preceding 2021 demonstrate that the total fertility rate in some countries has fallen below replacement levels—the minimum rate necessary for generational replacement of the population assuming no migration—with no evidence of this predicted rebound. The replacement level is generally accepted to be a TFR of at least 2.1.
Fertility rates declined in all countries and territories, but in 94 countries and territories in 2021, TFR remained above the replacement-level fertility of 2.1. Sub-Saharan Africa had the largest share of live births in 2021, and this region is projected to see an increase in the proportion of global live births by 2100. Fertility rates are forecasted to continue declining worldwide, with the number of countries with rates above replacement dropping to just six by 2100. Meeting UN Sustainable Development Goal (SDG) targets and implementing pro-natal policies may result in slightly higher fertility rates, but overall, fertility rates are expected to remain low.
Societies will transition from a condition of high fertility and high mortality with more young than old people to a state of low fertility and low mortality with an increasingly older population. These changes will have significant economic and societal consequences, including aging populations and declining workforces in higher-income countries and an increasing share of live births in the poorest regions of the world.
