Infant mortality rate is a population-related metric that monitors the deaths of newborn (and sometimes unborn) children, a small but heartbreaking subset of both the world's total births and its total deaths per day. Infant mortality is typically expressed as the number of infant deaths per 1,000 live births. In countries where infant mortality is high, it can often be attributed to one or more of the following factors: poverty, malaria, malnutrition, undeveloped infrastructure, and/or inadequate health care. Notably, these are all common concerns in underdeveloped, least developed, and developing countries. Many countries with high infant mortality rates also have high birth rates and fertility rates.
Around the world, the top causes of infant mortality include neonatal encephalopathy (problems with brain function due to lack of oxygen during birth), infections, complications of preterm birth, lower respiratory infections, and diarrheal diseases. The most frequent causes of death among infants that are only a few days old are different than those among older infants. Overall, the collective global infant mortality rate has significantly decreased in recent decades, dropping from approximately 140 per 1,000 live births in 1950-55 to 52.8 in 2000 and on to 27.4 in 2020.
Infant mortality in the United States is predominantly caused by congenital disabilities, pre-term birth and low birth weight, maternal pregnancy complications, Sudden Infant Death Syndrome, and injuries (such as accidental suffocation). The mortality rate in the United States was 5.44 in 2020. This rate was 50th among the 195 countries and territories measured, and significantly higher than in dozens of other developed countries such as Sweden (2.15), Japan (1.82), and Australia (3.14).
Upon examination, however, the discrepancy between the U.S. and other countries appears largely due to country-to-country differences in the way infant mortality statistics are compiled. Infant mortality is defined differently in different countries, and the U.S. definition is notably broader than that of most other countries.
For example, the United States Center for Disease Control defines "infant death" as any death of an infant that takes place between the start of pregnancy (conception) through the child's first birthday. On the other hand, the World Health Organization (WHO) includes only those children who die during pregnancy or the first 42 days (approximately six weeks) after birth. The fact that the United States' window of inclusion is 323 days (approximately 10.5 months) longer very likely contributes significantly to the United States' higher infant death totals. (A similar distortion can be seen in Sweden's sexual assault statistics.)
Additionally, some countries do not consider a child an infant until birth, and so do not include deaths that occur during pregnancy (stillborn, miscarriages, etc.) among their infant mortality rate totals. As a result of these varying definitions, while any infant mortality rate above 0.0 is worthy of concern, the rate in the U.S. is likely less dire compared to rates in other countries than it initially appears to be.
According to the most recent data, the US ranks 50th in infant mortality.
The country that has the lowest infant mortality rate in the world is Iceland.