Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100: a comprehensive demographic analysis for the Global Burden of Disease Study 2021
Level 3 - non-randomized controlled study
Level 3 by design analogy; comprehensive multi-country demographic time-series synthesis and forecasting model.
OpenAlex W4394019396 · doi:10.1016/s0140-6736(24)00550-6
What was done
The Global Burden of Disease Study 2021 estimated fertility indicators across 204 countries and territories from 1950 to 2021 using mixed-effects regression and spatiotemporal Gaussian process regression on 8,709 country-years of vital and sample registrations, 1,455 surveys and censuses, and 150 other sources. Future fertility metrics through 2100 were forecast using an ensemble meta-regression model of completed cohort fertility at age 50 (CCF50) incorporating female educational attainment, contraceptive met need, population density, and under-5 mortality under reference and alternative policy scenarios.
What was found
Global total fertility rate (TFR) fell from 4.84 (95% UI 4.63–5.06) in 1950 to 2.23 (2.09–2.38) in 2021. Annual livebirths peaked at 142 million (137–147) in 2016 and declined to 129 million (121–138) in 2021. In 2021, 94 countries and territories (46.1%) maintained TFR above replacement (>2.1), including 44 of 46 in sub-Saharan Africa. By 2050, global TFR is projected to reach 1.83 (1.59–2.08) with 49 countries (24.0%) above replacement. By 2100, global TFR is projected at 1.59 (1.25–1.96) with only 6 countries (2.9%, all in sub-Saharan Africa) remaining above replacement. Sub-Saharan Africa is projected to account for 54.3% (47.1–59.5) of global livebirths by 2100, up from 29.2% (28.7–29.6) in 2021.
Why it matters
This study provides an exhaustive historical baseline and long-term projection of the global demographic shift, highlighting that nearly all nations will face sustained below-replacement fertility while the majority of global livebirths concentrate in low-resource settings.
Limits
Projections up to 2100 rely on assumptions regarding female education, contraceptive access, and policy responses that carry wide uncertainty over multi-decade horizons. Data quality and completeness in vital registration systems varied substantially across historical country-years and regions.
Cited by
- supports A 2024 study published in The Lancet projects that by the year 2100, 97% of all countries and territories will have fertility rates too low to sustain their populations.
- supports The global fertility rate has dropped from an average of five children per woman in 1950 to 2.2 children per woman today.
- supports Projections indicate that by 2100, one in every two children born globally will be born in sub-Saharan Africa.