Glossary term
Infant mortality rate (IMR)
The number of deaths of infants under one year of age per 1,000 live births in a given year. One of the most sensitive summary indicators of population health — and historically a key driver of fertility behaviour, as falling infant mortality reduces the "demand" for large families.
IMR = (Deaths under age 1 in year ÷ Live births in year) × 1,000 Why IMR is a foundational demographic indicator
The infant mortality rate is often the first statistic cited when assessing a country's development level because it aggregates so many upstream determinants: quality of maternal care, access to clean water and sanitation, nutrition levels, vaccine coverage, and healthcare system strength. A low IMR signals that these systems are functioning; a high IMR signals failures across multiple dimensions simultaneously.
UNICEF and the WHO Global Health Observatory jointly produce the UN Inter-agency Group for Child Mortality Estimation (UN IGME) estimates, which are the standard reference. The World Bank publishes country-level IMR time series back to 1960.
The global decline — one of history's great achievements
The fall in infant mortality over the 20th century is one of the most consequential demographic changes in human history. In 1900 the global IMR was estimated at around 150–200 per 1,000 — meaning roughly 1 in 6 to 1 in 5 infants died before their first birthday. By 1990 it had fallen to 65. By 2022 it reached 27. This ~80% reduction over 120 years saved hundreds of millions of lives.
The decline is directly linked to the demographic transition: as child survival improved, parents needed fewer children to ensure some survived to adulthood. Falling IMR is therefore one of the primary triggers of fertility decline — not a consequence but a cause. The sequence — mortality falls first, fertility follows — explains the "growth gap" during Stage 2 of the demographic transition.
Where the gap remains
Despite dramatic global progress, the IMR gap between the richest and poorest countries is still approximately 35-fold. Sub-Saharan Africa accounts for the majority of all infant deaths globally, despite containing only about 15% of births. UNICEF's 2023 child mortality report found that a child in sub-Saharan Africa is 15 times more likely to die before age 5 than a child in Europe or North America.
The main causes in high-IMR settings are preterm birth complications, birth asphyxia, neonatal sepsis, pneumonia, and diarrhoea — all preventable or treatable with existing technologies. This is why the SDG 3 target calls for ending preventable deaths of newborns and children under 5, with all countries aiming for neonatal mortality ≤12 per 1,000 live births and under-5 mortality ≤25 per 1,000 by 2030.
Frequently asked questions
What is the infant mortality rate?
The infant mortality rate (IMR) is the number of deaths of children under one year per 1,000 live births in a given year. It is a standard indicator of population health. See UNICEF child survival data for country-level figures.
What is the global infant mortality rate today?
The global IMR was approximately 27 per 1,000 live births in 2022, down from 65 in 1990 — a ~60% reduction. Iceland and Japan record rates below 2; Sierra Leone and Chad exceed 70. The World Bank IMR database provides full country-level time series.
How does infant mortality relate to fertility?
When infant mortality falls, the "insurance" demand for extra births falls too — parents no longer need large families to ensure some children survive. Falling child mortality is one of the first triggers of the demographic transition: mortality falls, then fertility follows.
How is infant mortality different from child mortality?
Infant mortality covers deaths under age 1 per 1,000 births. Child mortality (under-5 mortality rate) covers deaths before age 5. UNICEF and WHO track both via the UN IGME. The under-5 rate is roughly 1.4–1.7× the IMR, with additional deaths from diarrhoea, pneumonia, and malnutrition in years 2–4.