US Infant Mortality: A Century of Dramatic Progress
It is one of the great untold success stories of modern life. In 1915, roughly one in ten American babies died before reaching their first birthday. Today that figure has fallen by more than 90%, to around one in 170 — a transformation driven by clean water, vaccines, antibiotics, and modern medicine. This guide charts the century-long collapse in U.S. infant mortality, explains what caused it, and asks why a country this wealthy still trails its peers.
What is the infant mortality rate?
The infant mortality rate counts deaths of babies before their first birthday per 1,000 live births. It's one of the most sensitive indicators of a society's overall health, because infant survival depends on so many things working together — sanitation, nutrition, maternal health, and access to medical care. The chart shows the U.S. rate plunging from a horrifying level a century ago to a small fraction of it today, one of the steepest sustained improvements in any health statistic.
A century of progress
In 1915, the U.S. infant mortality rate was about 100 per 1,000 — meaning roughly one in ten infants died in their first year. The decline since has been relentless and dramatic: the rate fell by more than 90% over the following century. Most of the early progress came from conquering the infectious diseases and unsanitary conditions that killed so many babies; later gains came from neonatal intensive care, vaccines, and better prenatal medicine.
Why infant deaths plummeted
The collapse in infant mortality tracks the rise of public health. Clean drinking water and milk pasteurization wiped out the diarrheal diseases that once killed countless infants. Vaccines and antibiotics tamed deadly infections. Prenatal care and hospital delivery made childbirth far safer, and neonatal intensive care units learned to save premature and critically ill newborns who would once have died. Each advance chipped away at a different cause of infant death.
Why the U.S. still lags wealthy peers
Despite this progress, the U.S. infant mortality rate remains higher than most other wealthy nations — a sobering fact for a country that spends more on health care than any other. The gap reflects deep disparities: infant mortality is far higher among lower-income families and for Black infants than white infants, driven by unequal access to prenatal care, higher rates of premature birth, and broader social and economic inequality. Closing that gap remains one of America's stubborn public-health challenges.
Frequently asked questions
What is the U.S. infant mortality rate?
Around 1 in 170 births today — a small fraction of the roughly 1 in 10 rate of a century ago, reflecting a decline of more than 90%.
How much has infant mortality fallen?
By more than 90% since 1915, when about one in ten American babies died before their first birthday. It's one of the steepest improvements in any health statistic.
Why did infant mortality fall so much?
Clean water and pasteurized milk, vaccines and antibiotics, prenatal care, hospital delivery, and neonatal intensive care each cut a major cause of infant death.
Why is U.S. infant mortality higher than other rich countries?
Despite high health spending, the U.S. lags due to deep disparities — much higher rates among lower-income families and Black infants, tied to unequal access to care and higher premature births.
What is the infant mortality rate measuring?
Deaths of babies before their first birthday per 1,000 live births — a sensitive indicator of a society's overall health and access to care.