SIDS Research Activities and Advances

Much of the Institute's research on SIDS is conducted through the Pregnancy and Perinatology Branch (PPB). Its efforts have included and still include studies on the causes and etiology of SIDS, ranging from basic research with animal models to more applied methods involving responses to environmental risk factors with the goal of developing tools to identify and protect high- risk infants; research on risk factors for SIDS, especially among certain portions of the U.S. population; and research to improve outreach designed to educate parents and caregivers about ways to reduce SIDS risk, especially among those populations with a higher incidence of SIDS.
Recent findings from Branch-supported research on SIDS include, but are not limited to, the following:

• Brain abnormalities of SIDS infants within the continued investigation of the underlying processes that may lead to SIDS. Almost 20 years of NICHD- and PPB-supported research have led to the important findings of a deficit in the neural network within the medullary raphe of the brainstem that is unique to SIDS infants. This network uses the neurotransmitter serotonin and controls heart rate, breathing, blood pressure, temperature, and arousal from sleep. Three-fourths of SIDS infants in one study had brainstem abnormalities. For more on this finding, visit http://www.nichd.nih.gov/news/
  releases/Pages/sids_serotonin.aspx. Ongoing studies on the medullary deficiency seek to understand the underlying basis of the deficiency and how this affects infants' inability to resuscitate themselves following life-threatening challenges such as hypoxia. Visit http://www.nichd.nih.gov/news/
  releases/Pages/020310-SIDS-
  linked-serotonin.aspx for additional information on this line of research.
• Infant sleep practices and how environmental factors impact SIDS risk. Ongoing studies on sleep position focus on the decreased arousal response in stomach sleepers compared with infants who sleep on their backs. NICHD researchers are studying sleep position decisions and other factors that influence SIDS risk that are common within certain racial or ethnic communities and lower-socioeconomic communities. The goal of these efforts is to improve the design, implementation, and effectiveness of risk reduction strategies for SIDS and causes of infant death associated with the sleep environment.
• Infants who sleep in the same bed with their mother are at greater risk for SIDS and other kinds of sleep-related death. However, infant care and public health experts have feared that sleeping separately might interfere with breastfeeding. NICHD-funded researchers recently found that more than half of women who were exclusively breastfeeding were following guidelines on sharing the sleeping room with their infants rather than sleeping with the baby.
• Potential genetic causes of SIDS. NICHD researchers identified a mutation in 5% to 10% of SIDS infants. The mutations were in a cardiac sodium-channel gene and have been found in congenital heart conditions and arrhythmia, which can lead to cardiac arrest. Recent studies have found rare mutations in several other genes that control cardiac rhythm that may be a potential cause for or contributor to some cases of SIDS.

To achieve its goals related to SIDS, NICHD supports and participates in a variety of other activities. Some of these activities are managed through the components listed above; others are part of NIH-wide or collaborative efforts in which NICHD participates. Some of these are listed below:

• The Safe to Sleep® Campaign (formerly Back to Sleep) aims to raise awareness about and to educate parents, caregivers, and health care providers on ways to reduce the risk of SIDS and other sleep-related causes of infant death. Since NICHD and its collaborators launched the campaign in 1994, the U.S. SIDS rate has declined by more than 50%, and the percentage of infants placed on their backs to sleep has more than tripled.
• The Prenatal Alcohol and SIDS and Stillbirth (PASS) Network is designed to conduct community-linked studies to investigate the role of prenatal alcohol exposure in the risk for SIDS and adverse pregnancy outcomes, such as stillbirth and fetal alcohol spectrum disorders, and how they may be interrelated. The main study in this PPB-funded network is the Safe Passages Study, which will follow 12,000 pregnant women through their pregnancies and their children's first year.
• The Collaborative Home Infant Monitoring Evaluation (CHIME) Study, now complete, was a multicenter cooperative study of home monitoring that aimed to determine whether home monitors are effective in identifying episodes that are dangerous to the infant's health.
• The National Infant Sleep Position (NISP) Study, conducted from 1992 to 2008, was a multicenter cooperative study of infant sleep aimed to assess infant care practices and dissemination of infant sleep position recommendations. The NISP Study examined factors that affect infant sleep position, including infant sleep position choices made by caregivers. The Study also examined other aspects of infant sleep environment and caregiver choices for infant sleep environment, including bed sharing with adults or other household members, within the context of SIDS, entrapment, overlay, and suffocation. Researchers are still analyzing data from the NISP Study.
• The Study of Attitudes and Factors Affecting Infant Care Practices (SAFE)  picks up where the NISP Study left off to further understand infant sleep practices and SIDS risks within racial/ethnic minority and lower socioeconomic communities. SAFE researchers will survey a nationally representative group of caregivers—meaning the ethnic backgrounds of caregivers in the study are similar to those of caretakers in the United States as a whole—to better understand the factors that make them more or less likely to follow safe sleep practices.