Feb 01

NICU Milk Storage

Mother nature never intended milk to be pumped and frozen, so we have to do our best to keep milk quality as high as possible.

Remember that fresh milk has live cells and special fat globules that are easy for your baby to digest.

Freezing milk kills these cells, and breaks up the fat globules, but bacteria live on. So ask your baby’s nurse if you can give baby fresh milk every day.

Freezing milk you can’t use now or for the future is important as you build your supply and wait for baby to learn to breastfeed.

The way milk is stored can be important to ease your workload and to minimize wasted milk.

Basic Rules Of Storage (May Vary By Hospital)

Never throw away milk without being sure it is not good.

Pump right into the storage bottles — they fit onto the pump — so the best calories and fat that cling to the plastic are not lost. Every time you pour milk into another container you leave important fats and calories behind

Milk Is Good For:

  • 4 hours at room temperature.
  • 4 days in the refrigerator.
  • 4-6 months in the freezer.
  • 12 months in a deep freezer.

Colostrum Storage

Most NICUs like the valuable colostrum in little syringes for first feedings or oral care.

Ask the nurse how long to do this so milk is not wasted.

Best Way To Freeze Milk

You can combine milk from both breasts together in one bottle.

You can mix fresh cold milk from different pumping times together- we call that pooling.

You can add warm milk to cold liquid milk.

Try and put the same amount of milk in each bottle before you freeze it- ask the nurses how much they recommend (usually 100 mLs).

Some hospitals may have you pool 24 hours of milk in a large bottle which makes all the feedings have the same calories and may ease your workload.

Label Your Milk Well

Your hospital may give you stickers with yours and your babies name or you can write your name on each bottle of milk.

Write the date and time on the milk container.

Note any special concerns or new medications on the milk bottle.

Types Of Milk Containers

Plastic breastmilk bags are great for working mothers, but are not durable enough in the hospital.

Most hospitals will give you as many bottles and labels as you need.

If you make a lot of milk consider asking for larger bottles from the NICU.

Milk that will be frozen and stay at home can be put in breastmilk bags.

Be sure to put your name and date on them just in case you want to donate it later.

Don’t Let The Hospital Run Out Of Your Milk

Keep your hospital bin full of milk so if you can’t visit they don’t run out.

Try and bring fresh milk every day for baby.

Sometimes frozen milk can develop a weird smell or taste for baby, ask the lactation nurse if you have any concerns. It is rarely a problem for the baby’s belly though they may not like the taste.


Lisa Stellwagen MD, FAAP
Professor of Clinical Pediatrics at UC San Diego Health