Basic information for topics, such as “What is it?” and “How many people are affected?” is available in the Topic Information section. In addition, Frequently Asked Questions (FAQs) that are specific to a certain topic are answered in this section.
- Does risk for infant mortality run in families?
- How is research making a difference in reducing infant mortality rates?
Many causes of infant mortality happen spontaneously, meaning that a family that has experienced the death of an infant isn’t necessarily at increased risk for additional loss. However, for some causes, the risk does apply to later generations.
In examining the leading causes of U.S. infant mortality:
- Birth defects. Some birth defects result from genetic conditions that might be passed on from parent to child. However, some genetic conditions—such as Down syndrome—occur spontaneously, meaning they are not passed down through a family. If a controllable risk factor led to a birth defect and that risk factor is not controlled or eliminated, the birth defect may also occur in other children. Learn more about risk factors for birth defects.
- Preterm birth. Women who have experienced a preterm birth are at increased risk of delivering early if they become pregnant again.1 Learn more about the risk factors for preterm birth.
- Sudden Infant Death Syndrome (SIDS). There is no evidence that an infant is at higher risk of SIDS because an older sibling died of SIDS. However, if certain SIDS risk factors or dangers in the sleep environment are not controlled or eliminated after the SIDS death of one infant, other infants in the family would be at increased risk for SIDS or other sleep-related causes of infant death.2
- Pregnancy complications. Depending on the specific complication, a second pregnancy may or may not be at increased risk. Learn more about common pregnancy complications.
- Accidental injuries. The term “accident” refers to something unplanned or unforeseen, so by its very nature it is unlikely to run in families. However, like other causes of infant mortality, if an unsafe situation is not made safer after one infant dies, then other infants in that situation would also be at risk for death.
Families who have experienced the death of an infant might find it helpful to speak with their health care provider, a genetic counselor, or a safety expert. These professionals can help families understand the cause of the infant’s death—if known—and can evaluate any risks to future children the family might want to have.
Research has contributed a great deal to reducing infant mortality in the United States and worldwide. Since the NICHD’s establishment in 1962, it has played a major role in many efforts to understand, reduce, and eliminate causes of and contributors to infant mortality. Below are some highlights of the Institute’s successes related to reducing infant mortality:
- Respiratory distress syndrome. In 1980, among preterm infants in the United States who developed this breathing disorder, which results from underdeveloped lungs, 4,989 died from the condition. By 2010, U.S. infant deaths from respiratory distress syndrome had plummeted to 514.3 This turn-around was the result of advances in respiratory technologies and the development of replacement lung surfactant—a sort of lung “grease” that is vital for breathing, but which preterm babies can’t yet make on their own. Research efforts of the NICHD and other NIH Institutes led to these advances.
- Sudden Infant Death Syndrome (SIDS). In 1993, more than 4,000 infants died of SIDS in the United States. In 1994, the NICHD, in collaboration with other organizations and agencies, launched the Safe to Sleep® campaign (then called Back to Sleep) to educate parents, caregivers, and health care providers about ways to reduce the risk of SIDS and other sleep-related causes of infant death. Since then, the U.S. SIDS rate has dropped by more than 50%. Learn more about progress in reducing SIDS.
- HIV/AIDS. As a result of research funded by the NICHD, the National Institute of Allergy and Infectious Diseases, and other organizations, the mother-to-child transmission rate of HIV in the United States dropped from 25% in the early 1990s to less than 1%.4,5 By virtually eliminating transmission of the virus, this research also nearly eliminated HIV/AIDS as a cause of infant mortality in the United States.
- Preterm birth. NICHD-led research found that giving a form of the hormone progesterone to women at risk for preterm birth because of a previous preterm birth greatly reduced the preterm delivery rate among these women.6 The finding was so significant that the American Congress of Obstetricians and Gynecologists issued a recommendation in 2003 that women at risk for preterm birth receive progesterone to prevent preterm birth in subsequent pregnancies.7 Later NICHD-funded research also found that giving progesterone to women with a short cervix—also a risk factor for preterm birth—reduced the risk of preterm delivery and reduced the risk of respiratory distress syndrome and death in their infants.8
- Birth asphyxia. According to the World Health Organization, about 1 million newborn babies around the world die each year from birth asphyxia—a lack of oxygen to the brain—in the moments before, during, and right after birth. Many of these deaths occur in resource-limited regions. The NICHD led an evaluation of the Helping Babies Breathe® program, in which skilled birth attendants who typically assist with childbirth in rural and resource-limited settings were trained in ways to resuscitate newborns. The evaluation showed a significant decrease in death rates in the first week after birth.9 Helping Babies Breathe® is now being implemented in more than 30 countries around the world.
By studying the causes of and contributors to infant mortality, the NICHD continues to add to a knowledge base that will further reduce infant deaths. Visit the NICHD Research Information section to learn more about the NICHD’s research efforts to reduce infant mortality in the United States and around the world.