What Can I Fortify Breast Milk With?

December 25, 2025 •

3 min read

Breast milk is the best food for most babies. However, the World Health Organization states that some infants, like premature babies, may not get enough nutrients. Fortification can help. So, what can you fortify breast milk with?

Quick Summary

Premature babies often need extra nutrients. Fortification with human milk fortifiers or preterm formulas, under medical supervision, ensures adequate growth and development. These steps may be necessary to support the baby's health.

Key Points

Medical Supervision: Fortification of breast milk should only occur under the supervision of a pediatrician or neonatal dietitian for safety.
Human Milk Fortifiers (HMF): These supplements have extra calories, protein, and minerals, which are mixed into breast milk.
Nutritional Goal: Fortification addresses that breast milk alone may not meet the needs of a rapidly growing premature baby.
Combination Feeding: Supplementing with preterm formula may be recommended, but proper preparation is essential.
Potential Side Effects: Infants may experience temporary feeding intolerance when fortification is initiated.
Temporary Measure: Fortification is often temporary until a premature infant's age reaches term. The medical team decides when to stop.

Why Is Fortification Necessary for Some Infants?

Premature infants have higher nutritional needs than full-term babies. These infants have missed the final months of pregnancy, when most nutrients and minerals are stored. Breast milk alone does not provide enough calories, protein, and minerals for their needs. Without fortification, these infants risk poor growth and bone development.

The Need for Higher Nutritional Intake

Increased energy demands: Premature babies need more calories per kilogram of body weight for growth.
Higher protein requirements: Essential for tissue and organ development.
Enhanced mineral content: Increased calcium and phosphorus are needed for bone health.
Micronutrient support: Fortification ensures sufficient levels of vitamins and minerals.

Medical Options to Fortify Breast Milk

Fortifying breast milk should only be done with medical advice. Improper fortification can cause health problems. Here are the approved methods for fortification:

Human Milk Fortifiers (HMF)

These are powders or liquids added to expressed breast milk.

Composition: HMFs contain protein, carbohydrates, calories, calcium, phosphorus, and other minerals and vitamins. Some are from cow's milk protein, others use human milk-derived protein.
Administration: In hospitals, HMF is mixed with breast milk in prescribed amounts. Parents are instructed on how to continue this at home.
Benefits: HMF provides essential nutrients while keeping the benefits of human milk.

Combination Feeding with Preterm Formula

In some cases, doctors may recommend supplementing with preterm formula.

Procedure: This can involve alternating feeds of breast milk and preterm formula or combining them.
Safety Warning: Never add powdered formula to breast milk without mixing it with water first. This can be dangerous. Always prepare formula separately and combine if directed.

Other Potential Supplements

Some pediatricians may recommend specific, single-nutrient supplements, on a case-by-case basis. These are not a substitute for a full fortifier.

Probiotics: Adding probiotics to breast milk may help promote good gut bacteria, but research is ongoing. Medical consultation is necessary.
Hindmilk: If only extra calories are needed, healthcare providers may suggest feeding with hindmilk, the higher-fat milk from the end of a pumping session.

Comparison of Fortification Methods


Feature	Human Milk Fortifier (HMF)	Combination Feeding (Preterm Formula)
Application	Powder or liquid added to expressed breast milk.	Separate feeds or pre-mixed liquid/powdered formula combined with breast milk.
Composition	Concentrated source of protein, carbs, fats, vitamins, and minerals.	Complete nutritional product, with some formulas designed for preterm needs.
Effect on Milk	Increases nutrient density while retaining human milk's benefits.	Can potentially alter taste, potentially increasing gassiness in some infants.
Nutritional Impact	Primarily designed to boost missing nutrients in human milk for preterm infants.	Delivers a complete, balanced nutritional profile, though lacks the unique non-nutritional factors of human milk.
Risks	Potential for feeding intolerance, mild metabolic acidosis, or NEC, though studies show overall safety.	Potential for increased risk of NEC compared to a strictly human milk-based diet, though still low.

Important Considerations and Risks

While beneficial, fortifying breast milk requires careful monitoring.

Feeding Intolerance: Some infants may experience feeding intolerance, such as spitting up or changes in stool, when fortification is introduced. This is usually temporary.
Infection Risk: Powdered fortifiers, like powdered formulas, carry a very small risk of bacterial contamination (e.g., Cronobacter).
Optimal Timing: The ideal time to introduce fortification varies. Early fortification can help prevent nutrient deficits, but it is typically started once the infant is tolerating a certain volume of enteral feeds.
Long-Term Effects: More research is needed regarding long-term neurodevelopmental and metabolic outcomes.
Stopping Fortification: The decision to stop fortification is made by the medical team based on the infant's age, weight gain, and overall health.

Conclusion

For premature or low birth weight infants who need extra nutrition, fortification is a safe practice. The primary method is adding human milk fortifier (HMF) to breast milk under a doctor's supervision. Combination feeding with preterm formula may also be used. Consult your baby's healthcare team before starting any fortification. This ensures the method is safe for your infant. The goal is to provide the necessary calories and nutrients. Remember that fortification is a temporary step to help a vulnerable infant's growth, not a reflection of the quality of your breast milk.

Frequently Asked Questions

No, never add dry formula powder directly to breast milk. Powdered formula must always be mixed with the correct amount of water first, following the manufacturer's directions.

The main reason is to boost the nutritional content for premature or low birth weight infants. They need more calories, protein, and minerals that breast milk alone cannot provide.

Yes, risks include feeding intolerance (digestive upset), and, in rare cases, mild metabolic acidosis or necrotizing enterocolitis (NEC). Medical professionals closely monitor these risks.

The duration of fortification is decided by your baby's doctor based on weight gain, growth, and health. It is often continued until the baby's due date.

Both exist. The choice depends on various factors. Some research suggests human milk-derived fortifiers may have a lower risk of complications. Your medical team will recommend the best option.

No, fortifying breast milk is a medical procedure. Do not do this without instructions from your baby's pediatrician or neonatal team. Improper ratios can lead to dangerous imbalances.

Your diet can affect the fatty acid profile of your milk, but it will not substantially change the calorie or protein content to the level needed for a preterm infant. Eating a balanced diet and staying hydrated is still important for your health and milk supply.