Human milk, fortification and preterm nutrition

Branch 1: Assessment of growth

Examiner: This infant is growing poorly. What is your assessment? Expected response: This infant is failing to achieve the intrauterine growth rate. The target is 15 to 20 g/kg per day, and she is gaining only 6 g/kg per day, which places her on a trajectory toward extrauterine growth restriction. Her current unfortified mother's milk at 20 kcal per ounce delivers roughly 80 kcal/kg per day and 1.2 g/kg per day protein, well below the ESPGHAN targets of 110 to 135 kcal/kg per day and 3.5 to 4 g/kg per day protein [1].

Branch 2: Fortification strategy

Examiner: How will you improve her nutrition? Expected response: Multicomponent human milk fortifier should be introduced immediately, since the enteral volume of 120 mL/kg per day has already exceeded the 80 to 100 mL/kg per day threshold for fortification. Standard fortification raises the caloric density from 20 to 24 kcal per ounce, increasing energy to approximately 96 kcal/kg per day and protein toward the 3.5 to 4 g/kg per day target. If growth remains inadequate, I would escalate to 26 or 30 kcal per ounce and use adjustable fortification guided by blood urea nitrogen [1].

Branch 3: Human milk evidence

Examiner: Why not just switch to preterm formula, which is nutritionally more complete? Expected response: Mother's own milk remains the first-line substrate even though it requires fortification, because of its protective properties. The Lucas and Cole study demonstrated that formula feeding increases the risk of necrotising enterocolitis approximately six-fold compared with exclusive human milk feeding. Human milk provides immunoglobulins, lactoferrin, oligosaccharides, and growth factors that protect and mature the preterm gut — benefits that formula cannot replicate [2].

Branch 4: Fortifier choice

Examiner: This is an extremely preterm infant. Would you use bovine or human milk-derived fortifier? Expected response: For an infant born at 26 weeks and under 1000 g, there is evidence to favour an exclusively human milk-based diet where available. The Sullivan trial demonstrated that an exclusively human milk-based diet, combining mother's milk with human milk-derived fortifier, was associated with a lower rate of NEC and surgical NEC than a diet incorporating bovine milk-based products. The liquid formulation is preferred in infants under 1500 g for sterility [3].

Branch 5: Long-term outlook

Examiner: What are the consequences if this growth trajectory is not corrected? Expected response: Persistent growth failure predicts adverse neurodevelopment. Cohort data show that extrauterine growth restriction at discharge is associated with higher rates of cerebral palsy, lower cognitive scores, and increased neurodevelopmental disability. Correcting the growth trajectory through fortification is a clinical priority, not a cosmetic concern. The family should be counselled about the importance of continued milk expression and the role of fortification in optimising long-term outcomes [1].