The infant mortality rate measures how many babies die before their first birthday out of every 1,000 born alive in a given year. It’s one of the most widely used indicators of a country’s overall health and well-being, reflecting everything from the quality of prenatal care to nutrition, poverty levels, and access to medical services. In 2023, the United States recorded a rate of 5.61 infant deaths per 1,000 live births, while some regions of sub-Saharan Africa saw rates several times higher.
How It’s Calculated
The formula is straightforward: take the number of deaths among children under one year of age during a specific time period, divide it by the total number of live births during that same period, and multiply by 1,000. A country that records 500 infant deaths and 100,000 live births in a year has an infant mortality rate of 5.0 per 1,000.
Health agencies further divide infant mortality into two subcategories based on the timing of death. Neonatal mortality covers deaths in the first 28 days of life, when babies are most vulnerable to complications from birth itself. Postneonatal mortality covers deaths between 28 days and 364 days, when causes like infections, sleep-related incidents, and injuries become more prominent.
Why It’s Considered a National Health Benchmark
Researchers and policymakers treat the infant mortality rate as a barometer for the overall welfare of a population. A high rate signals problems that go well beyond hospital delivery rooms. It often points to gaps in maternal nutrition, limited access to prenatal care, higher poverty, and weaker public health infrastructure. A low rate, by contrast, suggests a society where pregnant women can get consistent medical attention and newborns receive timely interventions when something goes wrong.
Because it captures so many overlapping social and medical factors in a single number, the infant mortality rate is used in cross-country comparisons more than almost any other health statistic. It’s also a core target of the United Nations Sustainable Development Goals, which call on all countries to end preventable deaths of newborns and children under five by 2030.
Leading Causes of Infant Death
Globally, the top killers of newborns are premature birth, complications during delivery (such as oxygen deprivation or trauma), neonatal infections, and congenital anomalies. Together, these account for nearly 4 in every 10 deaths among children under five worldwide.
In the United States, the breakdown looks slightly different because many infectious causes have been reduced through vaccination and sanitation. The five leading causes of infant death in 2023 were:
- Congenital malformations (birth defects involving the heart, brain, or other organs), responsible for 20.0% of infant deaths
- Preterm birth and low birth weight, accounting for 14.5%
- Sudden infant death syndrome (SIDS), at 7.2%
- Unintentional injuries, at 6.4%
- Maternal complications of pregnancy, at 5.7%
Global Rates and Regional Gaps
Progress over the past three decades has been dramatic. Total deaths among children under five dropped from 12.8 million in 1990 to 4.8 million in 2023, a 59% decline. The global under-five mortality rate fell from 93 per 1,000 live births in 1990 to 37 in 2023.
That progress has been deeply uneven. Sub-Saharan Africa had the highest neonatal mortality rate in 2023, at 26 deaths per 1,000 live births, followed by Central and Southern Asia at 21 per 1,000. A baby born in sub-Saharan Africa is 14 times more likely to die in the first month of life than a baby born in Australia or New Zealand. Wealthier nations with strong healthcare systems typically report rates below 5 per 1,000.
Racial and Ethnic Disparities in the U.S.
The national U.S. rate of roughly 5.6 per 1,000 masks sharp disparities. As of 2018 data, non-Hispanic Black infants died at a rate of 10.8 per 1,000 live births, nearly three times the rate for Asian infants (3.6) and more than double the rate for non-Hispanic White infants (4.6). Native Hawaiian and Pacific Islander infants faced a rate of 9.4, and American Indian infants 8.2.
These gaps persist even when controlling for factors like income and education, pointing to systemic differences in healthcare access, quality of care, chronic stress, and environmental exposures. In some states, the disparities are even starker. In Colorado in 2016, for example, the infant mortality rate among Black infants was 10.7, compared with 4.0 for non-Hispanic White infants. In Alaska, American Indian infants had the highest rate of any group, averaging 9.3 per 1,000 from 2016 to 2018.
What Lowers the Rate
Many infant deaths are preventable. The most effective interventions start before pregnancy even begins. Reaching a healthy weight, managing chronic conditions like diabetes or hypertension, getting adequate folic acid to prevent neural tube defects, and addressing substance use all reduce risk for the leading causes of infant death.
Once pregnant, early and consistent prenatal care is the single most important step. Regular checkups allow providers to catch warning signs of preterm labor, track fetal growth, and manage conditions like preeclampsia before they become emergencies. Adequate prenatal nutrition helps ensure babies reach a healthy birth weight, which is one of the strongest predictors of survival.
After birth, safe sleep practices have had a measurable impact on SIDS rates. The Safe to Sleep campaign, which encourages placing babies on their backs in a clear crib with no loose bedding, pillows, or soft objects, has been credited with saving a significant number of lives since its launch. Newborn screening programs, now standard in most developed countries, catch metabolic and genetic conditions early enough for treatment to make a difference.
At a population level, the countries with the lowest infant mortality rates share common features: universal access to prenatal care, paid parental leave, strong immunization programs, and public health systems that reach rural and low-income communities. The gap between the best-performing and worst-performing countries remains one of the clearest measures of global health inequality.