Infant Mortality

Infant mortality refers to the death of an infant between 1 day and 1 year of age. (Deaths before age 28 days can also be classified as neonatal mortality.) There are many causes of infant mortality, ranging from infections to accidents.

NICHD supports research on many causes of and conditions that can lead to infant death, including Sudden Infant Death Syndrome (SIDS) and other sudden, unexpected infant deaths, congenital anomalies, and preterm birth. The Institute also studies ways to prevent or reduce the risk of these causes and conditions to reduce infant mortality rates and improve infant health outcomes.

About Infant Mortality

What is infant mortality?

Infant mortality is the term used to describe the death of a baby that occurs between the time it is born and 1 year of age. If a baby dies before age 28 days, the death can also be classified as neonatal mortality.

The infant mortality rate—that is, the number of infant deaths out of every 1,000 live births—is an important factor in understanding a population’s overall health because many factors that contribute to infant deaths also affect the health of everyone in a population.1 For example, access to medicine, trained healthcare providers, clean water, and food affect everyone’s health, but can also have a dramatic effect on infant mortality rates.

The term “infant mortality” refers only to deaths that occur after birth. Deaths that occur before birth are usually classified as either stillbirth or pregnancy loss. Stillbirth is the death of a fetus at or after 20 weeks of pregnancy. Pregnancy loss, or miscarriage, is a fetal loss that occurs earlier in pregnancy.


  1. Centers for Disease Control and Prevention. (2012). Infant mortality. Retrieved July 23, 2013, from

What causes infant mortality?

There are many different causes of infant mortality, from infection to congenital anomalies or accidents. The main causes of infant mortality in the United States are different than the main causes of infant death around the world. In addition, in the United States and worldwide, the most common causes of infant death in the first weeks after birth are different than those that occur later in the first year.

There is a difference between causes of infant mortality and contributors to infant mortality. A cause leads directly to a death. In contrast, a contributor is a risk factor that makes the death more likely to happen. Learn more about the risk factors for infant mortality.

Causes of Infant Mortality in the United States

The most common causes of death in the United States in 2011 were the following:1

  1. Congenital anomalies
  2. Preterm birth and low birth weight
  3. Sudden Infant Death Syndrome (SIDS)
  4. Pregnancy complications
  5. Accidents

The causes of infant mortality in the United States have changed somewhat over the past several decades. In 1980, congenital anomalies, SIDS, preterm birth/low birth weight, and pregnancy complications were among the top five causes of death, as they are now. At that time, respiratory distress syndrome (RDS), instead of accidents, was also on the top-five list.2 However, with the development of treatments for RDS, deaths from this cause have declined significantly.

Overall, the rate of infant death in the United States has dropped during the last several decades.

Causes of Infant Mortality Worldwide

Globally, the top five causes of infant death in 2010 (the most recent year for which data were available) were the following:3,4

  1. Neonatal encephalopathy, or problems with brain function after birth. Neonatal encephalopathy usually results from birth trauma or a lack of oxygen to the baby during birth.
  2. Infections, especially blood infections
  3. Complications of preterm birth
  4. Lower respiratory infections (such as flu and pneumonia)
  5. Diarrheal diseases

This ranking is an average for all infant mortality from birth to age 1 year. It does not reflect the fact that the major causes of death in older infants are different from those in younger infants. For example, congenital anomalies are a top cause of death worldwide in the days just after birth, but not among older infants. In contrast, malaria is a top cause of death around the world in infants older than 1 month of age, but not in younger infants.3,4

The top five causes of global infant mortality were the same for 2010 as they were for 1990. However, deaths from certain causes dropped dramatically in those 20 years. In particular, many fewer babies died of lower respiratory infections and diarrheal diseases in 2010 than did in 1990.3,4


  1. Hoyert, D. L., & Xu, J. (2012). Deaths: preliminary data for 2011. National Vital Statistics Reports, 61(6). Retrieved July 23, 2013, from (PDF 891 KB)
  2. Centers for Disease Control and Prevention. (2012). Table 13. Infant mortality rates, fetal mortality rates, and perinatal mortality rates by race: United States, selected years 1950–2010. Health, United States – 2012 ed. Atlanta, GA: Author.
  3. Lozano, R., Naghavi, M., Foreman, K., Lim, S., Shibuya, K., Aboyans, V., et al. (2012). Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet, 380(9859), 2095–2128. PMID: 23245604
  4. Institute for Health Metrics and Evaluation (IHME) (2013). Causes of death visualization. Retrieved November 5, 2014, from external link

Are there ways to reduce the risk of infant mortality?

Often, there are no definite ways to prevent many of the leading causes of infant mortality. However, there are ways to reduce a baby’s risk. Researchers continue to study the best ways to prevent and treat the causes of infant mortality and affect the contributors to infant mortality. Consider the following ways to help reduce the risk:

Congenital anomalies are currently the leading cause of infant mortality in the United States.1 There are many different kinds of congenital anomalies, and they can happen in any pregnancy.

There are several things pregnant women can do to help reduce the risk of certain congenital anomalies, such as getting enough folic acid before and during pregnancy to prevent neural tube defects. Learn more about some risk factors for congenital anomalies.

There is currently no definitive way to prevent preterm birth, the second most-common cause of infant mortality in the United States.1 However, researchers and healthcare providers are working to address the issue on multiple fronts, including finding ways to stop preterm labor from progressing to a preterm delivery and identifying ways to improve health outcomes for infants who are born preterm. Preterm infants commonly have a low birth weight, but sometimes full-term infants are also born underweight. Causes can include a mother’s chronic health condition or poor nutrition. Adequate prenatal care is essential to ensuring that full-term infants are born at a healthy weight.2,3

There are some known risk factors for preterm birth—including having had a preterm birth with a previous pregnancy—and women with known risk factors may receive treatments to help reduce those risks. But in most cases, the cause for preterm birth is not known, so there are not always effective treatments or actions that can prevent a preterm delivery.

Researchers and healthcare providers are also working to understand the health challenges faced by infants born preterm or at a low birth weight as a way to develop treatments for these challenges. For instance, preterm infants are at high risk for serious breathing problems as a result of their underdeveloped lungs. Treatments such as ventilators and steroids can help stabilize breathing to allow the lungs to develop more fully. In addition, studies suggest that infants born at low birth weight are at increased risk of certain adult health problems, such as diabetes, high blood pressure, and heart disease.4

During pregnancy, the mother’s health, environment, and experiences affect how her fetus develops and the course of the pregnancy. By taking good care of her own health before and during pregnancy, a mother can reduce her baby’s risk of many of the leading causes of infant mortality in the United States, including congenital anomalies, preterm birth, low birth weight, Sudden Infant Death Syndrome (SIDS), and certain pregnancy complications.5,6,7

Women don’t need to wait until they are pregnant to take steps to improve their health. Reaching a healthy weight, getting proper nutrition, managing chronic health conditions, and seeking help for substance use and abuse, for example, can help a woman achieve better health before she is pregnant. Her improved health, in turn, can help to reduce infant mortality risks for any babies she has in the future. Learn more about pre-pregnancy care.

Once she becomes pregnant, a mother should receive early and regular prenatal care. This type of care helps promote the best outcomes for mother and baby. Learn more about prenatal care.

SIDS is defined as the sudden, unexplained death of an infant younger than 1 year of age that remains unexplained even after a thorough investigation. SIDS is the third-leading cause of infant mortality in the United States.

SIDS is one type of death within a broader category of causes of death called sudden unexpected infant death (SUID). The SUID category includes other sleep-related causes of infant death—such as accidental suffocation—as well as infections, vehicle collisions, and other causes.8

As SIDS rates have been declining in the last few decades, rates of other sleep-related causes of infant death have been increasing. Accidental injury is the fifth-leading cause of infant mortality in the United States.

Although there is no definite way to prevent SIDS, there are ways to reduce the risk of SIDS and other sleep-related causes of infant death. For example, always placing a baby on his or her back to sleep and keeping baby’s sleep area free of soft objects, toys, crib bumpers, and loose bedding are important ways to reduce a baby’s risk.8 The NICHD-led Safe to Sleep® campaign (formerly the Back to Sleep campaign) describes many ways that parents and caregivers can reduce the risk of SIDS and other sleep-related causes of infant death.

Newborn screening can detect certain conditions that are not noticeable at the time of birth, but that can cause serious disability or even death if not treated quickly. Infants with these conditions may seem perfectly healthy and frequently come from families with no previous history of a condition.

To perform this screening, healthcare providers take a few drops of blood from an infant’s heel and apply them to special paper. The blood spots are then analyzed. If any conditions are detected, treatment can begin immediately.

Most states screen for at least 29 conditions, but some test for 50 or more conditions. Infants who are at increased or high risk for a condition because of their family history can undergo additional screening—beyond what states offer automatically—through a healthcare specialist.

Since this public health program was initiated 50 years ago, it has saved countless lives by providing early detection and intervention and by improving the quality of life for children and their families.


  1. Hoyert, D. L., & Xu, J. (2012). Deaths: preliminary data for 2011. National Vital Statistics Reports, 61(6). Retrieved July 23, 2013, from (PDF 891 KB)
  2. HealthyPeople2020. (2021). Maternal, infant, and child health. Retrieved October 28, 2021, from
  3. Peleg, D., Kennedy, Colleen, M., & Hunter, S.K. (1998). Intrauterine growth restriction: Identification and management. American Family Physician, 58(2), 453–460.
  4. Hovi, P., Andersson, S., Eriksson, J. G., Järvenpää, A. L., Strang-Karlsson, S., Mäkitie, O., et al. (2007). Glucose regulation in young adults with very low birth weight. New England Journal of Medicine, 356, 2053–2063.
  5. CDC. (2012). Infant mortality. Retrieved July 23, 2013, from
  6. Steward, A.J. et al. (1995). Antenatal and intrapartum factors associated with SIDS in New Zealand Cot Study. Journal of Paediatrics and Child Health. 31(5), 473-478.
  7. Iyasu et al. (2002) Risk factors for SIDS among Northern Plains Indians. Journal of the American Medical Association, 288, 2717-2723.
  8. American Academy of Pediatrics Task Force on Sudden Infant Death Syndrome. (2011). SIDS and other sleep-related infant deaths: Expansion of recommendations for a safe infant sleeping environment. Pediatrics, 128, 1030-1039.
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