Nutrition for Premature Infants in the NICU

For a time, healthcare staff will care for your baby in the neonatal intensive care unit (NICU). There are several ways to feed babies while they’re in the NICU. A healthcare provider may start to feed your baby through an IV (intravenous line). This is a tube that goes into the vein. A tube may be used to send formula or human milk into the baby’s stomach (a gavage feeding). Your baby may be able to go directly to breast or bottle-feeding. The best method depends on your baby’s health and gestational age. Your baby will likely be feeding from a breast or bottle before leaving the NICU to go home.

What are babies fed in the NICU?

  • Total parenteral nutrition (TPN). This is a solution that provides all the nutrition your baby needs. Your baby gets this through their vein. Healthcare providers give TPN to most very early preemies. This is because their digestive systems are not yet mature, so they can’t absorb enough nutrition through regular feedings.

  • Human milk. Your baby will get the best nutrition and protection from your own milk. It can be given with a gavage feeding, at the breast, or with a bottle. Many preemies learn to breastfeed while in the NICU. Ask the NICU staff about the best way to pump and store milk for your baby. If your baby is a preemie, the milk may be mixed with a protein and mineral supplement (fortifier) to help your baby's growth. Mom's milk benefits premature babies because it reduces the chance of getting infections and is easiest to digest. Many NICUs will give donor milk from a milk bank to very small preemies whose moms don't have enough milk yet.

  • Formula. Special formulas are designed for the needs of preemies for whom human milk is not available. The healthcare team will give this to your baby, with a gavage feeding or a bottle, if you are unable to provide milk or choose not to and if donor milk is not available.  

How does a baby move from TPN to full breast or bottle-feeding?

If your baby has started on TPN, moving to full breast or bottle-feeding may take  3 to 4 weeks. This depends on your baby’s gestational age. A baby is often able to start learning to feed from your breast or a bottle by 32 to 34 weeks gestation. Meanwhile, gavage feeding will provide most of the baby's nutrition until they can fully feed by mouth.

The type of feeding that goes into the stomach rather than the vein is called enteral nutrition. Enteral feedings start with a small amount of milk or formula. The amount of breast or formula feedings is increased as the baby grows stronger. At the same time, TPN is decreased. The goal over time is to work up to full enteral feeding. This is often calculated as 150 to180 mL of milk or formula, per kilogram, per day.

In some cases, a baby who is having a health problem may need to go back to TPN for a time. If this happens, milk or formula feeding will be started again when the baby is ready. Babies who aren't ready to take all their feedings by mouth can still have full enteral feedings by gavage, without TPN.

Online Medical Reviewer: Donna Freeborn PhD CNM FNP
Online Medical Reviewer: Liora C Adler MD
Online Medical Reviewer: Stacey Wojcik MBA BSN RN
Date Last Reviewed: 12/1/2022
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