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The purpose of preemie formula is to supply a preemie with extra nutrients, protein, and vitamins in order to promote growth and weight gain. Although preemie formula is beneficial, it also carries an elevated likelihood of causing necrotizing enterocolitis (NEC), which is a serious intestinal illness that can result in death.
What is preemie formula, exactly?
Preemie formula is a specialized type of baby formula that aims to enhance the growth and advancement of premature infants. While experts recommend breastfeeding as the optimal nutrition for premature babies, it may not be feasible for some mothers.
While regular baby formula provides adequate nutrition for full-term infants, it falls short for preemies. As premature babies require more nutritional assistance to gain weight and grow, especially in terms of bone growth. This is because preemies miss out on all or some of the third trimester, the period between the 27th and 40th week of pregnancy, when babies develop their bones.
Preemie formula is enriched with greater levels of calcium and phosphate to support bone development. Additionally, babies need additional amounts of folic acid and vitamins D, E, K, and iron.
Premature babies often require extended hospitalization in the neonatal intensive care unit (NICU) for close monitoring to ensure their healthy development. During their stay, they will typically receive preemie formula or breast milk enriched with a human milk fortifier.

What are the different types of preemie formula?
Not all premature infants respond equally well to standard preemie formulas, and there are different types of baby formulas tailored to meet the unique needs of each baby. It is important to avoid homemade baby formula, as it may not be safe, and it is crucial that infants receive all the nutrition they require.
Preemies are more susceptible to digestive issues than full-term babies, such as developing an allergy to cow’s milk, which is a common ingredient in most standard formulas. In such cases, pediatricians may recommend a special type of non-dairy formula.
Specialized preemie formulas may include amino acid-based, lactose-free, and hypoallergenic options. If a formula specifically designed for preemies is unavailable, doctors may suggest adding a formula fortifier.
Amino Acid based formula:
Preterm infants who experience cow’s milk allergies or difficulties digesting fat are often recommended to use amino acid-based formulas. Instead of using protein from milk, these formulas employ simple proteins known as amino acids.
Well-known brands of these formulas include EleCare, Enfamil Nutramigen AA, and Neocate.
Lactose free formula:
Preemies who experience difficulty digesting lactose, the natural sugars found in cow’s milk, may benefit from lactose-free formula. However, certain formulas that lack lactose may still contain dairy proteins.
Infants with cow’s milk allergies may continue to face issues with lactose-free formulas that have dairy proteins. In such cases, a soy-based formula may be a more viable option. Popular lactose-free brands include Similac Sensitive and Enfamil LactoFree.
Hypoallergenic formula:
Hypoallergenic baby formula is formulated for infants with allergies to soy and cow’s milk. Research has demonstrated that hypoallergenic formula can prevent atopic diseases and treat milk protein allergies in high-risk infants.
Similac Alimentum and Enfamil Nutramigen are among the widely recognized brands of hypoallergenic formula.

How to choose a preemie formula:
In the NICU, the appropriate formula for a baby is typically selected by the hospital. Upon discharge, a preemie may be able to transition to full-term formula or breast milk supplemented with full-term formula.
Some preemies may still require additional nutritional support if they have experienced growth difficulties. In these situations, a pediatrician may recommend a specialized “post-discharge” preemie formula or breast milk fortified with such formula. The post-discharge preemie formula provides slightly fewer nutrients than preemie formula but more than full-term formula.
While doctors will always recommend breastfeeding as the optimal choice for infants due to the nutritional composition of breast milk, preemies may require human milk fortifiers to enhance vitamin and mineral intake. However, if breastfeeding is not an option or formula is needed for any other reason, choosing preemie formula is best done in consultation with the baby’s physician.
What about switching to preemie formula?
Preemie formulas are formulated to accelerate catch-up growth in premature infants. If babies were not initially fed preemie formula or transitioned to full-term formula or breastfeeding when leaving the hospital, the baby’s doctor may decide to switch back to preemie formula if they are not meeting their catch-up growth targets.
Be vigilant for any signs of discomfort or distress in your baby and inform your baby’s doctor right away. These symptoms often include fussiness, refusal to eat, or a sensitive abdomen. Your baby’s doctor will advise you on what to look for. You may need to experiment with a few different formula options, but always inform your doctor before making a formula switch.
Are there side-effects of preemie formula?
Digestion-related side effects are the most common in preemie formula, including gas, stomach upset, or diarrhea. Preemies with a cow’s milk or soy allergy may also experience skin issues and digestive problems, which can sometimes affect their breathing. If your baby exhibits any of these symptoms, inform your pediatrician immediately.
Necrotizing enterocolitis (NEC) is one of the most severe side effects of baby formula in premature infants. NEC is an inflammatory bowel disease that results in the death of intestinal tissue. When the intestinal walls weaken, they may rupture, allowing bacteria from the gut to enter the bloodstream and cause sepsis, a dangerous blood infection.
NEC affects about one in 1,000 preemies, and studies have shown that premature babies on exclusive formula diets are at the highest risk of developing the disease.
When should you stop using preemie formula?
Pediatricians may advise parents to discontinue the use of preemie formula if the baby experiences adverse reactions or no longer requires it.
If your baby experiences any side effects, it’s essential to consult their doctor immediately. It’s not advisable to switch or discontinue the use of baby formula without consulting a doctor. Your baby’s pediatrician or neonatologist will provide the most suitable advice.
Doctors will keep track of your preemie’s growth progress and inform you when to discontinue the use of preemie formula. The baby’s growth will be measured to determine when they attain the size of a full-term baby. Typically, preemies catch up with full-term infants’ growth within the first year of their life.
A note about preemie formula lawsuits:
Mead Johnson and Abbott Laboratories have faced lawsuits from some parents whose preemies developed necrotizing enterocolitis (NEC) after being fed cow’s milk-based Enfamil and Similac preemie formulas. These lawsuits also include human milk fortifiers made from cow’s milk. In some cases, the preemies died from NEC or complications related to the disease.
The lawsuits claim that Abbott and Mead Johnson did not provide adequate warnings about the risk of NEC associated with their products. Despite studies indicating that cow’s milk formula-fed preemies have a higher risk of NEC, the companies continued to produce these products.
To date, there have been no recalls of preemie formulas related to NEC. However, in February 2022, Abbott issued a recall of some Similac baby formulas produced at their Michigan factory due to potential Cronobacter bacteria contamination.
For more information about these lawsuits, you can read this article on the DrugWatch website.