What is a significant characteristic of SUID cases?

SUID, or Sudden Unexplained Infant Death, is characterized by the unexpected death of an infant, typically during sleep. This designation encompasses a range of scenarios, including SIDS (Sudden Infant Death Syndrome), and it is marked by the fact that the infant was previously healthy and the death occurs without a clear explanation even after thorough investigation. This unexpected nature poses significant challenges for families and healthcare providers alike, and it emphasizes the necessity for comprehensive investigative protocols.

In contrast to the other options, which imply specific conditions or circumstances that do not universally apply to SUID, the essential feature is indeed the unforeseen aspect of these tragedies. Medical negligence is not a required characteristic, and the causes are not easily diagnosed; in fact, many SUID cases remain a mystery despite extensive investigation. Moreover, while many SUID events occur during the night due to the nature of sleep, they can also happen during daytime naps, making "only occurring during the night" a misleading characterization. Therefore, the hallmark of SUID cases is their unexpected occurrence in infants, highlighting the need for awareness and preventive measures to reduce risk factors associated with infant sleep safety.