Other Infant Mortality FAQs

Basic information for topics, such as “What is it?” is available in the About Infant Mortality section. Answers to other frequently asked questions (FAQs) specific to infant mortality are in this section.

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:

  • Congenital anomalies. Some congenital anomalies 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 congenital anomaly and that risk factor is not controlled or eliminated, the congenital anomaly may also occur in other children. Learn more about risk factors for congenital anomalies.
  • 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 healthcare 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 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 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, NICHD, in collaboration with other organizations and agencies, launched the Safe to Sleep® campaign (then called Back to Sleep) to educate parents, caregivers, and healthcare 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 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. 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, NICHD continues to add to a knowledge base that will further reduce infant deaths. Visit NICHD Research Information section to learn more about NICHD’s research efforts to reduce infant mortality in the United States and around the world.


  1. Centers for Disease Control and Prevention (CDC). (2013). Preterm birth. Retrieved July 24, 2013, from http://www.cdc.gov/reproductivehealth/maternalinfanthealth/PretermBirth.htm
  2. 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. PMID: 22007004
  3. CDC. (2012). Table 23. Leading causes of death and numbers of deaths, by age: United States, 1980 and 2010. Health, United States – 2012 ed. Atlanta, GA: Author.
  4. Davis, S. F., Byers, R. H. Jr, Lindegren, M. L., Caldwell, M. B., Karon, J. M., Gwinn, M. (1995). Prevalence and incidence of vertically acquired HIV infection in the United States. JAMA, 274(12), 952–955.
  5. Centers for Disease Control and Prevention. (2006). Achievements in Public Health: Reduction in Perinatal Transmission of HIV Infection—United States, 1985–2005. MMWR, 55(21), 592–597.
  6. Meis, P. J., Klebanoff, M., Thom, E., Dombrowski, M. P., Sibai, B., Moawad, A. H., et al. (2003). Prevention of recurrent preterm delivery by 17 alpha-hydroxyprogesterone caproate. New England Journal of Medicine, 348(24), 2379–2385. PMID: 12802023
  7. American College of Obstetricians and Gynecologists. (2003). ACOG committee opinion. Obstetrics & Gynecology, 102(5 Pt 1), 1115–1116. PMID: 14672496
  8. Hassan, S. S., Romero, R., Vidyadhari, D., Fusey, S., Baxter, J. K., Khandelwal, M., et al. (2011). Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial. Ultrasound in Obstetrics & Gynecology, 38(1), 18–31. PMID: 21472815
  9. Carlo, W. A., McClure, E. M., Chomba, E., Chakraborty, H., Hartwell, T., Harris, H., Lincetto, O., & Wright, L. L. (2010). Newborn care training of midwives and neonatal and perinatal mortality rates in a developing country. Pediatrics, 126(5), e1064–1071.
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