IBCLC Practice Exam 2026 – Complete Preparation Guide

Classic galactosemia is the condition that precludes breastfeeding due to metabolic issues in infants. This genetic disorder affects the body's ability to metabolize galactose, a simple sugar found in lactose and thus in breast milk. Infants with classic galactosemia cannot properly process galactose because they lack the enzyme galactose-1-phosphate uridyltransferase. When they consume lactose through breastfeeding, galactose accumulates in the system, leading to potentially serious complications such as liver damage, cognitive impairment, and other systemic issues.

In contrast, lactose intolerance is not typically a concern in infants, as the condition is rare in that age group and often resolves with maturation of the digestive system. Milk protein allergy can cause gastrointestinal and other allergic responses, but it does not necessarily require the complete avoidance of breastfeeding as alternative feeding strategies can often be employed. Lastly, reflux is a common condition in infants that can often be managed without discontinuing breastfeeding, and it does not stem from a metabolic deficiency. Thus, classic galactosemia is the primary condition in the infant that necessitates avoiding breastfeeding due to its metabolic implications.