What percentage of weight loss is considered physiological for preterm infants?

In preterm infants, a weight loss of up to 10% is often considered physiological and typical during the first few days of life. This is due to a variety of factors including the transition from intrauterine to extrauterine life, changes in fluid balance, and feeding practices. Weight loss beyond this threshold, particularly up to 15% or more, may indicate potential issues such as inadequate feeding or other clinical concerns requiring further evaluation.

Thus, a weight loss of 15% is above the physiological range for preterm infants and should raise awareness among caregivers and healthcare professionals to monitor the infant more closely. While an infant may lose weight naturally as part of this transition, significant or unexpected weight loss can lead to complications, so it is crucial to distinguish between normal variations and concerning trends in weight loss for this vulnerable population.