What constitutes an abnormal weight loss in newborns?

Abnormal weight loss in newborns is defined as a loss of 10% or more of their birth weight. It is common for newborns to lose some weight shortly after birth due to factors such as fluid loss and the adjustment to feeding, so a small loss of weight is generally considered normal. However, when the weight loss exceeds 10%, it may indicate potential issues such as feeding difficulties, dehydration, or other underlying health problems that necessitate further evaluation and intervention.

The distinctions made in the other options clarify that while some weight loss in the first week is expected, a significant loss beyond 10% raises concerns. Weight stabilizing after 24 hours is typical, but it does not address the overall concern of percentage weight lost. Thus, recognizing the threshold of 10% is crucial in assessing the health and wellbeing of a newborn.