Keep babies safe from positional asphyxia.

• Position: SIDS

Thirteen babies die suddenly and unexpectedly every day in the U.S. These deaths typically are attributed to SIDS (sudden infant death syndrome), which is a diagnosis of exclusion. If there is no scientific evidence to show that an infant died from a particular disease, condition, foul play, etc., it is up to the medical examiner or pathologist to make the determination. Some will list the cause of death as SIDS, and others will list it as asphyxiation.

To further complicate matters, there are no universally accepted guidelines in the examination of these infant deaths. Eight years ago, public health officials at the Centers for Disease Control and Prevention, Atlanta, Ga., launched a case registry to log SIDS deaths. The idea was to track deaths at the state level, monitor trends, and to gather data that could improve death-scene investigations and ultimately might help prevent future deaths. However, since 2009, this registry has only expanded from five states to 18.

The term "sudden and unexpected infant death" (SUID) or SIDS is used to describe all such deaths, regardless of cause. Cases of SUID/SIDS that remain unexplained after a complete autopsy and review of the circumstances of death and clinical history are classified as SIDS.

What is the cause of SIDS? "It is unclear whether SIDS occurs during sleep itself or during the many transitions between sleep and arousal that occur during the night, since such deaths are typically not witnessed. No single definition of SIDS is universally accepted, and contradictions among SIDS studies are due in part to the use of various...