Choosing the Best Formula for Your Preemie

Does Your Preemie Need a Special Kind of Milk?

feeding a baby
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With the many infant formulas on supermarket shelves, mothers of preemies may be confused about the best product for premature babies. Choosing a formula is definitely a decision that should be made with your neonatologist or pediatrician, but learning about the different types can help you and your doctor to make an informed decision.

Regular Formula

Most formulas for infants are made from cow's milk and designed for full-term babies.

Although science has not been able to craft an infant food with all of the nutritional and immunological benefits of breast milk, infant formula is a safe alternative. Modern formula is enriched with iron and fatty acids to promote brain development, along with all of the nutrients that growing babies need.

Examples: Similac Advance, Enfamil LIPIL, Nestle Good Start

Preemie Formulas

Premature babies and low birth weight babies often need special formulas to catch up on their growth, so that they will grow faster both while they are in the NICU and after they get home.

  • Pre-discharge formulas: When preemies first start taking milk feedings, doctors start with small amounts of formula at a calorie ratio that mimics breast milk. As babies get more used to feedings, doctors may start using higher-calorie milk to help babies grow more quickly. In the NICU, doctors use products designed for newborn preemies. These formulas have more protein than others and can be mixed together to offer higher-calorie preparations.

    Examples: Similac Special Care, Enfamil Premature LIPIL

  • Preemie discharge formulas: Before premature or low-birth-weight babies are discharged from the hospital, they are typically changed to a preemie discharge formula. These products have higher calories and more protein, vitamins, and minerals than regular infant formulas, so that catch-up growth started in the hospital can continue past discharge.

    Examples: Similac Neosure, Enfamil Enfacare, Cow & Gate Nutriprem 2

  • Human milk fortifiers: Premature or low birth weight infants who are breastfed or receiving expressed breast milk may require more calories than breast milk provides. In cases where doctors feel like fortifying breast milk is the best choice to enhance growth, human milk fortifiers are used. These products are typically cow's milk based.
    Human milk fortifiers are powders or liquids added to breast milk to increase the amount of protein and calories in the milk. Human milk fortifiers are used with premature and small babies to help them to gain weight faster and catch up to their peers. Human milk fortifiers are usually cow’s milk formula products, although soy, hypoallergenic, and lactose-free formulas can also be used to fortify breast milk.
  • One California-based company also manufactures a human milk fortifier made from donor breast milk.

    If you are pumping milk for your premature baby, your doctor may prescribe HMF to be added to your baby's breast milk. Although moms of premature babies have breast milk that is often higher in calories than moms of full-term babies, it's still important to add extra protein to your milk.

Formulas for Digestive Difficulties

Premature babies with digestive issues may benefit from changing their usual formula to a different blend.

Formulas for sensitive stomachs are designed for full-term babies and may not have enough calories for preemies, so never change to one of the products below without talking with your pediatrician.

  • Soy formulas: The protein in cow's milk can be difficult for some babies to digest. Babies with milk allergies may have diarrhea, sometimes with blood, or may have skin or respiratory problems. Soy proteins don't contain cow's milk, they are soy-based instead, and may help to alleviate symptoms of feeding intolerance.

    Examples: Similac Isomil, Enfamil ProSobee, Nestle Good Start Soy

  • Hypoallergenic formulas: Some babies are allergic to both cow's milk proteins and soy proteins. Hypoallergenic formulas contain pre-digested proteins, so babies who are allergic to milk proteins are usually able to tolerate hypoallergenic blends. These products are also lactose-free (see below).

    Examples: Similac Alimentum, Enfamil Nutramigen

  • Lactose-free formulas: Some babies may not have enough lactase, the enzyme used to digest the milk sugar lactose. Because these babies don't digest milk sugars well, they may be fussy or cry excessively. Lactose-free formulas may help these babies cry less and feel more comfortable.

    Examples: Similac Sensitive, Enfamil LactoFree

  • Amino acid-based formulas: Some babies with severe stomach problems may not be able to break down even the predigested proteins found in hypoallergenic formulas. For these infants, a formula that contains free amino acids (the building blocks of proteins) may be the only option. Amino acid formulas are suitable for children who have severe or life-threatening food allergies, who have had surgery on their intestines, or who have other severe gastrointestinal problems. These products are lactose-free and may contain special fats for children who have difficulty absorbing fats from regular formulas.

    Examples: EleCare, Enfamil Nutramigen AA, Neocate


Kanabar, D., Randhawa, M., and Clayton, P. "Improvement of Symptoms of Infant Colic Following Reduction of Lactose Load with Lactase." Journal of Human Nutrition & Dietetics. October 2001 14; 359-363.

Cirgin Ellett, DNS, RN, CGRN, Marsha."What is Known About Infant Colic?" Gastroenterology Nursing March/April 2003; 26; 60-65.

Gerber. Nestle Good Start Formulas. 

Enfamil. "Infant Products." from

Similac. Similac Baby Formula.