Fortifying breast milk involves adding specific nutrients to expressed human milk to enhance its caloric and protein content. This medically guided intervention is primarily intended for vulnerable infants with higher-than-average nutritional requirements. The main goal of fortification is to support the rapid growth and development of babies, particularly those born prematurely or experiencing a failure to thrive. This adjustment ensures the infant receives adequate nutrition to match the growth rate they would have experienced in the womb.
The Nutritional Rationale for Fortification
Infants born prematurely, especially those with a very low birth weight (VLBW), miss the significant transfer of nutrients that naturally occurs across the placenta during the third trimester. While unfortified human milk is the optimal food for term infants, its nutritional density is often insufficient to meet the accelerated demands of a pre-term baby. These infants require high rates of “catch-up” growth to support the maturation of their organs and neurological systems.
The most common deficiencies in unfortified breast milk for this population are protein, calories, and specific minerals. Protein is necessary for building new tissue and supporting overall growth. Calcium and phosphorus are also required in higher concentrations to enable bone mineralization, a process that largely occurs in the final weeks of gestation. Without sufficient supplementation, pre-term infants are at risk for impaired growth rates and conditions like metabolic bone disease of prematurity. Fortification aims to increase the nutrient concentration to support a growth rate similar to that of a fetus in utero.
Specialized Fortifiers Versus Standard Formula Powder
The two primary methods for fortification are using specialized Human Milk Fortifiers (HMFs) or adding standard infant formula powder. HMFs are the standard of care in neonatal intensive care units (NICUs) for VLBW infants, designed to provide highly concentrated protein, vitamins, and minerals. These products are often made from bovine milk protein that is sometimes partially hydrolyzed, making the nutrients easily digestible for a delicate system.
Standard formula powder, particularly preterm formula powder (PTF), is a common alternative, especially once the infant is discharged or requires less intensive support. Studies have shown that PTF fortification can be non-inferior to HMFs for short-term weight gain and may even be associated with a lower incidence of feeding intolerance in some infants. However, using formula powder requires extremely precise measurement to avoid issues like hyperosmolarity, a high concentration of dissolved particles difficult for a premature infant’s gut to handle. The choice between HMF and formula powder is a medical decision that relies on the infant’s specific nutritional needs, tolerance, and available resources.
Step-by-Step Guide to Safe Preparation
The safe preparation of fortified milk begins with strict hygiene to prevent bacterial contamination. Thoroughly wash your hands, and ensure all bottles, measuring tools, and feeding equipment have been sterilized and are completely dry. Use either fresh breast milk, refrigerated milk, or milk that has been safely thawed, as fortifiers should not be added directly to frozen milk.
The next step is the accurate measurement of the expressed breast milk (EBM) volume, typically using a syringe or a carefully calibrated bottle. Measure the fortifier precisely according to the healthcare provider’s prescription, which may be a specific number of scoops or grams per volume of EBM. Since the ratio is calculated based on the infant’s needs, any deviation can lead to under- or over-fortification.
Once the fortifier is added to the milk, mix it gently by swirling the container rather than shaking it vigorously. Shaking can damage beneficial proteins and fats in the breast milk, reducing its nutritional integrity. Ensure the powder is fully dissolved without creating excessive foam. The fortified milk should then be fed to the infant immediately or stored appropriately.
Important Safety and Storage Protocols
Fortified breast milk has a much shorter shelf life than unfortified expressed milk because added nutrients can promote bacterial growth. Once the fortifier has been mixed in, the milk should be used within 24 hours if kept refrigerated at 4°C or below. If the fortified milk is warmed for a feeding, it must be used within one hour and any remaining contents discarded to minimize bacterial proliferation. Fortified milk should never be refrozen after preparation, as the freezing process can alter the texture and nutrient composition of the fortifier, potentially separating the components. Always store prepared fortified milk at the back of the refrigerator where the temperature is most stable, and discard any leftovers that the baby does not finish during a feeding session.