What do we know about infant mortality in the U.S. and comparable countries?


Infant mortality (the death of an infant within the first year of life) is a widely-reported indicator of population health. This chart collection highlights key infant mortality trends and demographic variation within the United States and also explores infant mortality rates in the U.S. compared to countries that are similarly wealthy and sizable (based on GDP and GDP per capita).

Overall, the U.S. and comparable countries have seen a decrease in infant mortality rates in recent years, but the U.S. has been slower to improve its consistently higher average rate of infant deaths, and significant disparities exist within the U.S. Although these gaps are not very clearly understood (in part due to limited cross-national comparability and availability of data), we consider available data and recent research to highlight some of the better-understood factors contributing to the U.S.’s relatively high rates of infant death.

The U.S. infant mortality rate has improved over time


Over the past decade, the United States has seen reduced infant mortality. From 2007 to 2017, the U.S. infant mortality rate dropped by 14 percent (from 6.75 to 5.79 infant deaths per 1,000 live births). Among infant deaths, neonatal deaths are those which occur up to 27 days after birth, whereas postneonatal deaths are those occurring when the infant is 28 to 364 days of age. While both neonatal and postneonatal death rates have declined (by 13 and 17 percent from 2007 to 2017, respectively), the larger share of infant deaths has consistently been neonatal deaths.

Two thirds of infant deaths in the U.S. occur within a month after birth


While the majority of infant deaths in the U.S. occur less than 28 days after birth (the neonatal period), a substantial share occur 28 to 364 days after birth (the postneonatal period). In 2017, 66 percent of infant deaths occurred in the neonatal period, and 40 percent of all infant deaths occurred specifically within the first 24 hours of birth. About a third of infant deaths (34 percent) occurred in the postneonatal period.

Infant mortality rates are relatively high in southern states


The U.S.’s overall infant mortality rate is 5.79 deaths per 1,000 live births, but infant mortality rates vary from state to state, with a concentration of high rates in the South and parts of the Midwest. At the state level, infant mortality ranges from a low of 3.66 deaths per 1,000 live births in Massachusetts to a high of 8.73 in Mississippi. According to the National Center for Health Statistics, eleven states have infant mortality rates significantly lower than the national rate (CA, CO, CT, ID, MA, MN, NH, NJ, NY, ND, and WA), and fifteen states and the District of Columbia had significantly higher rates (AL, AR, GA, IN, KY, LA, MD, MI, MS, NC, OH, OK, SC, SD, and TN).

Mortality rates are higher than average among infants born to mothers who are Black, American Indian and Alaska Natives, and Pacific Islanders


There are significant racial disparities in infant mortality rates in the United States. Non-Hispanic Black mothers experience the highest infant mortality rate among all racial and ethnic groups (10.97 infant deaths per 1,000 live births), as well as the highest rates of preterm birth (delivery before 37 weeks of gestation) and low birth weight, both of which are leading causes of infant death. Mothers who are American Indian or Alaska Native and Native Hawaiian or other Pacific Islander also experience a higher than average infant mortality rate (9.21 and 7.64 deaths per 1,000 live births, respectively). The infant mortality rate among Hispanic mothers is similar to the national average (5.10 deaths per 1,000 live births), while rates among White and Asian mothers are lower than average (4.7 and 3.8 deaths per 1,000 lives births, respectively).

Researchers have long considered a variety of complex factors in an effort to better understand racial disparities in infant mortality, including infant health; maternal demographics, health, and behavior; medical care before, during, and after birth; and home and social environments before and after birth. Studies consistently indicate that socioeconomic disadvantage is linked to higher risk of adverse birth outcomes both in the U.S. and other highly industrialized countries, with substantial variation in how socioeconomic factors impact birth outcomes for different racial and ethnic groups.

However, studies also increasingly note that socioeconomic disadvantages alone may not fully account for why Black mothers and their infants face such a disparity in adverse maternal and infant health outcomes in the U.S., and researchers focusing on the substantial Black-White infant mortality gap have generally found that controlling for maternal background factors also does not fully explain the disparity. Notably, recent research exploring U.S. maternal and infant health disparities discusses structural racism as a primary risk factor for African-American mothers and their infants, largely due to the complex stress it places on mothers throughout their life.

Neonatal mortality is highest among infants of Black mothers


Racial and ethnic disparities in infant mortality exist in both the neonatal and postneonatal period. In 2017, neonatal mortality was highest among infants of non-Hispanic Black mothers (7.16 deaths per 1,000 live births, compared to the national average of 3.85). Neonatal mortality was also above average among infants of non-Hispanic American Indian or Alaska Native mothers (4.77), was similar to the national average among infants born to both non-Hispanic Pacific Islander (3.82) and Hispanic (3.56) mothers, and was below average among infants born to White (3.04) and Asian (2.71) mothers.

Postneonatal mortality was higher than the national average of 1.94 deaths per 1,000 live births for infants of non-Hispanic American Indian or Alaska Native mothers (4.41), non-Hispanic Black mothers (3.82), and non-Hispanic Pacific Islander mothers (3.82).

Infant mortality is highest among mothers under age 20


Infant mortality varies considerably based on maternal age. The rate of infant mortality is highest among mothers under age 20 (9.0 deaths per 1,000 live births) and lowest among mothers aged between 30-34 years old (4.8 deaths per 1,000 live births).

Congenital malformations are the most common cause of infant death in the U.S.


In 2017, 68 percent of all infant deaths in the U.S. were attributable to the 10 leading causes shown in the chart above. Congenital malformations were the underlying cause of 21 percent of infant deaths, and short gestation and low birth weight together accounted for 17 percent of infant deaths in the U.S.

The leading causes of infant death in the U.S. vary before and after the infant is one month old


The primary causes of infant deaths vary by age of the infant at time of death. Within the first month after birth, short gestation and low birth weight are together the leading cause of neonatal mortality (at a rate of 0.95 deaths per 1,000 live births), followed by congenital malformations (0.87 deaths per 1,000 live births) and maternal complications (0.37 deaths per 1,000 live births). In the postneonatal period, the leading causes of death are congenital malformations complications (0.37 deaths per 1,000 live births, Sudden Infant Death Syndrome (SIDS), and accidents (each accounting for about 0.3 deaths per 1,000 live births). 

Infant mortality is higher in the U.S. than in comparable countries


The U.S. infant mortality rate (5.8 deaths under one year of age per 1,000 live births) is 71 percent higher than the comparable country average (3.4 deaths). Research indicates socioeconomic inequality in the U.S. is likely a primary contributor to its higher infant mortality, along with differential reporting methods. For example, a recent American Economic Journal study compared U.S. infant mortality to that of Austria, Belgium, Finland, and the United Kingdom, concluding that data reporting differences may explain up to about 30 percent of the gap between the U.S. and these European countries. The study finds that higher postneonatal mortality in the U.S. accounts for 30 to 65 percent difference and suggests socioeconomic conditions among disadvantaged groups in the U.S. may account for most of its excess postneonatal mortality.

Accounting for differential reporting methods, U.S. infant mortality remains higher than in comparable countries


When countries have different methods for reporting infant deaths, it is primarily a matter of how they report deaths among infants with very low odds of survival. According to the OECD, the United States and Canada register a higher proportion of deaths among infants weighing under 500g, which inflates the infant mortality rate of these countries relative to several European countries that count infant deaths as those with a minimum gestation age of 22 weeks or a birth weight threshold of 500g.

Our analysis of available OECD data for the U.S. and some similarly large and wealthy countries finds that when infant mortality is adjusted to include only those infant deaths that meet a minimum threshold of 22 weeks gestation or 500g in birth weight, the U.S. infant mortality rate is still higher than the average for those comparable countries with available data (4.9 vs 2.9 deaths per 1,000 live births). Without adjusting for data differences, the U.S. infant mortality rate appears to be 84 percent higher than the average for the same set of comparable countries. (Note that this comparison was limited to 2016 data and could not include data for Australia, Canada, and Germany, which are included in the previous chart’s comparable country average for 2017.)

Infant mortality has declined more slowly in the U.S. than in comparable countries


While differences in data collection likely explain some of the variance in infant mortality rates by country, this should not affect the relative rates of change over time, assuming data collection methods have not changed considerably. From 2000 to 2017, the infant mortality rate in the U.S. fell from 6.9 to 5.8 deaths per 1,000 live births, an improvement of 16 percent. Over the same period of time, the comparable country average improved by 26 percent, falling from 4.6 to 3.4 deaths per 1,000 live births.

The infant mortality gap between the U.S. and comparable countries is more pronounced among postneonatal deaths


Relative to comparable countries on average, the U.S. has 63 percent more neonatal deaths (3.9 vs 2.4 deaths per 1,000 live births) and 90 percent more postneonatal deaths (1.9 vs 1.0 deaths per 1,000 live births).

Neonatal mortality in the U.S. has improved more slowly than in comparable countries


From 2000 to 2017, neonatal deaths (deaths less than a month after birth) decreased by 15 percent in the U.S. and by 23 percent in comparable countries. Cross-national data reporting differences may explain some of the U.S.’s apparently lagging improvement.

Perinatal mortality in the U.S. is similar to comparable countries on average


Perinatal mortality rates, which reflect both early neonatal and some fetal deaths, are considered an indicator of the quality of antenatal and perinatal care. The U.S. perinatal mortality rate is similar to the average rate across comparable countries (6.0 and 5.9 deaths per 1,000 live births in 2016, respectively) and relatively lower than the rate in some similarly wealthy countries. It is not clear if this variation reflects the quality of newborn care in the U.S., as international comparisons of perinatal mortality rates require careful scrutiny due to differences in registration practices.