Preemie Formula

Preemie formula is designed to provide more nutrients, protein and vitamins than regular baby formula to help a preemie grow and gain weight. Preemie formula is effective, but it also comes with a higher risk of necrotizing enterocolitis (NEC), a potentially fatal intestinal disease.

Last Modified: September 5, 2023
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What Is Preemie Formula?

Preemie formula is baby formula specifically designed to boost the growth and development of premature babies. Experts recommend breast milk from the baby’s mother as the best food for premature infants, but sometimes it’s not possible for a mother to breastfeed.

Regular baby formula has adequate nutrition for full-term infants but isn’t enough for preemies. Because they were born early, preemies need more nutritional support to gain weight and grow, particularly when it comes to bone growth.

The 27th to 40th week of pregnancy, the third trimester, is when babies develop their bones, and preemies miss out on all or part of this stage of development. Preemie formula contains higher amounts of calcium and phosphate to support bone growth. Babies also need extra folic acid and vitamins D, E, K and iron.

Similac Preemie Formula NeoSure vs. Full-Term 360 Total Care Brands:
NutrientPreemie FormulaAmount Per ServingInfant FormulaAmount Per Serving
CaloriesSimilac NeoSure100Similac 360 Total Care100
ProteinSimilac NeoSure2.8 gSimilac 360 Total Care2.07
FatSimilac NeoSure5.5 gSimilac 360 Total Care5.60
CarbsSimilac NeoSure10.1 gSimilac 360 Total Care10.5
Linoleic AcidSimilac NeoSure750 mgSimilac 360 Total Care1000mg
CalciumSimilac NeoSure105 mgSimilac 360 Total Care78 mg
NiacinSimilac NeoSure1950 mcgSimilac 360 Total Care1050 mcg
BiotinSimilac NeoSure9 mcgSimilac 360 Total Care4.4 mcg
IronSimilac NeoSure1.8 mgSimilac 360 Total Care1.8 mg
Folic AcidSimilac NeoSure25 mcgSimilac 360 Total Care15 mcg
PotassiumSimilac NeoSure142 mgSimilac 360 Total Care105 mg

Preterm infants will usually stay in the hospital neonatal intensive care unit, or NICU, a little longer for observation and to make sure they are thriving. While in the hospital they will typically receive preemie formula or breast milk fortified with a human milk fortifier.

Types of Preemie Formula

Not all babies will respond well to standard preemie formulas, and there are different types of baby formulas to fit a baby’s special needs. You shouldn’t use homemade baby formula because it may not be safe and it’s important that babies receive all the nutrition they need.

Preemies may be more prone to digestive issues than full-term infants. For example, preemies may develop a cow’s milk allergy and most standard formulas are made with cow’s milk. In these cases, a pediatrician may recommend a special type of nondairy formula.

Special types of preemie baby formula might be amino acid-based, lactose-free and hypoallergenic. If a special baby formula isn’t made specifically for preemies, doctors may also suggest adding a formula fortifier.

Amino Acid-Based Formula

Amino acid-based formulas are recommended for preterm infants with cow’s milk allergies or trouble digesting fat. These formulas use simple proteins called amino acids instead of protein from milk.

Popular brands include EleCare, Enfamil Nutramigen AA and Neocate.

Lactose-Free Formula

Preemies who can’t digest lactose, the sugars in cow’s milk, may benefit from a lactose-free formula. However, some formulas do not contain lactose but still made from dairy proteins.

Babies with a cow’s milk allergy may still have trouble with lactose-free formulas that contain dairy proteins. In some cases, using a soy-based formula may help. Popular lactose-free brands include Similac Sensitive and Enfamil LactoFree.

Hypoallergenic Formula

Hypoallergenic baby formula is designed for babies who have soy and cow’s milk allergies. Studies have shown hypoallergenic formula prevents atopic disease and treats milk protein allergies in high-risk infants.

Popular brands include Similac Alimentum and Enfamil Nutramigen.

Choosing a Preemie Formula

In the NICU, the hospital typically chooses the formula best suited for the baby. After a preemie leaves the hospital NICU, they may be ready to switch to full-term formula or breast milk supplemented with full-term formula.

Some preemies may still require more nutritional support if they have had difficulty growing. In these cases, pediatricians will recommend a special “post-discharge” preemie formula or breast milk fortified with this formula. Post-discharge preemie formula has slightly less nutrients than preemie formula but more than full-term formula.

When it comes to breastfeeding vs. baby formula, doctors will always recommend breastfeeding as the best choice because of the beneficial makeup of breastmilk. Preemies will need human milk fortifiers to add extra vitamins and minerals. But, if mothers can’t breastfeed or need to use formula for any reason, choosing preemie formula is a decision best made with input from the baby’s doctor.

Switching to Preemie Formula

Preemie formulas are designed to speed up growth, also called catch-up growth, in premature babies. If babies weren’t initially fed preemie formula or transitioned to full-term formula or breastfeeding when leaving the hospital, a baby’s doctor may decide to switch back to preemie formula if they aren’t meeting their catch-up growth goals.

Keep an eye on your baby for any signs of discomfort or distress and tell your baby’s doctor right away. These typically include being fussy, refusing to eat or a tender belly. Your baby’s doctor can tell you what signs to look out for. You may need to try a couple of different formula options, but you should always tell your doctor before switching formulas.

Lawsuit Information
Lawsuits are being filed by parents whose children were diagnosed with necrotizing enterocolitis (NEC) after consuming cow's milk-based formula. Learn more.
View Lawsuits

Preemie Formula Side Effects

Most preemie formula side effects are digestion-related and include gas, upset stomach or diarrhea. If a baby has an allergy to cow’s milk or soy, they may have digestive issues and skin issues. In severe cases, it may also affect breathing. Tell your baby’s doctor right away if your baby shows any of these symptoms.

One of the most serious side effects of baby formula in preemies is necrotizing enterocolitis. NEC is an inflammatory bowel disease that causes tissue in the intestines to die. Weakened intestinal walls may rupture and allow bacteria from the gut into the blood and cause sepsis, a serious blood infection.

About one in 1,000 preemies develops NEC, and studies have shown that premature babies on exclusive formula diets are at the highest risk for developing the disease.

When to Stop Using Preemie Formula

Doctors may recommend stopping preemie formula if the baby has a bad reaction to it or if they no longer need it.

If your baby begins suffering side effects, make sure to talk to their doctor right away. Switching baby formula or stopping baby formula isn’t recommended without first speaking to your baby’s doctor. The pediatrician or neonatologist will give you the best course of action.

Doctors will monitor your preemie’s growth progress and tell parents when they can stop using preemie formula. They will measure the baby’s growth to see when they catch up to a full-term baby’s size. Preemies typically catch up within their first year of life.

Preemie Formula Lawsuits

Some parents filed preemie formula lawsuits against Mead Johnson and Abbott Laboratories when their preemie developed NEC after being fed cow’s milk-based Enfamil and Similac preemie formulas. In addition to Similac and Enfamil preemie formulas, human milk fortifiers made from cow’s milk are also included in lawsuits.

In some cases, the preemie died from NEC or complications of the disease.

According to the baby formula lawsuits, Abbott and Mead Johnson failed to include warnings about the risk of NEC. They also continued making cow’s milk products although several studies have shown that cow’s milk formula-fed preemies are at higher risk of NEC.

There have been no preemie formula recalls related to NEC. However, in February 2022 Abbott issued a Similac baby formula recall for some lots produced at its Michigan factory for potential Cronobacter bacteria contamination.

Please seek the advice of a medical professional before making health care decisions.