Upon palpation of the abdomen, which behavior indicates that a preterm newborn is in pain?

Observing a preterm newborn’s behavior during palpation of the abdomen can provide crucial insights into their comfort level and possible pain response. Fist clenching and thrashing are common indicators of discomfort or pain in infants. When a newborn exhibits these behaviors, it suggests that they are experiencing distress or discomfort, which is a critical sign for healthcare providers to assess further.

In contrast, behaviors such as a relaxed and calm demeanor, sleeping soundly, or being quiet and still would indicate that the newborn is likely at ease, and not experiencing any significant pain. These behaviors do not correlate with signs of distress and thus would not suggest that the newborn is in pain. Therefore, the presence of fist clenching and thrashing during abdominal palpation clearly highlights the infant's discomfort, making it the correct response from the choices provided.