Three Simple Rules for Storing Your Breast Milk

by Dr. Michele Brown OB/GYN and Renate Abstoss IBCLC

baby with bottleWhile life with children can sometimes become a juggling act, most of us have learned how to keep all the balls in the air. For a new mother with a job outside the home, however, the simple desire to continue breastfeeding her baby may seem impossible. It's not!

Don't Give Up!

It's a well known fact that breast feeding has significant benefits to both mother and baby. 60% of the 4 million pregnant women in America are currently employed and the majority of these new mothers will want to return to the workforce soon after delivery. This should not be a deterrent for promoting optimal infant health and therefore, it becomes extremely important for women to be encouraged to continue to breast-feed their newborns in a convenient way while still carrying on their daily work lives.

Since women are not available for demand feeding, it is vital they know how to use a breast pump and how to store milk so that another caregiver can provide milk for the newborn. This article deals with the proper way to store breast milk.

How Long Can I Store Milk?

Breast milk storage follows the rule of 3:

  1. Freshly pumped breast milk at room temperature (77 degree F or 25 degree C) should be used within 3 hours.
  2. Freshly pumped breast milk that is refrigerated (39 degree F or 4 degree C) should be covered and used within 3 days.
  3. Freshly pumped breast milk can be frozen (4 degree F or -16 degree C) for up to 3 months. (Check your home freezer for temperature—freezers may run as low as 0 degrees F and deep freezes may run at -10 degrees F.)

Can I refrigerate or freeze milk after it has been sitting out for the 3 hours?

No. One cannot follow one step after the other. The milk is at the end of its shelf life after one of the above 3 steps is followed.

However, if small amounts of milk are pumped at a sitting, it is possible to put the freshly pumped milk in the refrigerator to cool and then immediately add it to frozen milk in order to obtain the accumulated 4 oz. feeding. The milk will often freeze in layers and needs to be shaken before use.

Shelf life is determined by the older milk in the container. Some sources suggest using the milk for longer periods of time, but often the taste of the milk deteriorates due to breakdown of flavonoids, which may cause the baby to reject the milk. The taste deterioration occurs before the milk becomes contaminated due to elevated bacterial counts.

What Guidelines Should I Follow for Freezing Milk?

Similar to the way food stock is rotated in a supermarket, the newest milk should be placed in the back of the freezer where it is colder and older milk moved to the front, as a reminder to use it first. Dates should be placed on the container. If frozen for storage in a day care center, place the baby's name on the container. Freezing in small allotments of 2 to 4 oz. is recommended since it takes less time to defrost and less is wasted if the baby is unable to finish the feeding. Leave room at the top of the container when freezing since liquid expands when frozen.

Disposable bags with freezer ties are fine to use since they take up less refrigerator space. Less expensive generic bags are just as good as brand name bags. It is a good idea to double bag the milk to eliminate and risk of contamination due to leakage. Several smaller bags can be placed in a larger zip lock bag. Plastic or glass storage containers can also be used, but there is risk of breakage. Avoid containers that have BPA.

How Do I Reheat Breast Milk?

Milk that has been frozen or refrigerated can be reheated to room temperature by putting it in a cup of hot water or in a bottle warmer. Refrigerated milk may take about 5 minutes to reheat and frozen milk may take about 20 minutes. Frozen milk left in the refrigerator to thaw takes approximately 12 hours.

Never microwave frozen or refrigerated breast milk. This will destroy some of the beneficial properties of the milk. In addition, microwaved milk may be unevenly heated which could be potentially dangerous to the newborn. Milk that has been defrosted may appear layered due to the fact that the fat content will rise to the top. You may want to mix the milk by shaking before feeding to the baby.

Further Information

The La Leche League has a website that reviews storage guidelines. Guidelines may vary depending upon the lactation consultant. Also, the Human Milk Banking Association of North America (HMBANA) is a non-profit organization that sets standards and operates human milk banks in Canada, Mexico, and the United States. They provide information to the medical community on the storage of human milk and also serve as a resource for both potential milk donors and recipients for mothers that are unable to provide breast milk. We must keep in mind that there are new mothers who for one reason or another are not able to breast feed (gender, medications, illness, decreased supply, adoption/surrogate birth, etc.) and want the best nutrition and immunity protection for their baby.

Renate Abstoss IBCLC was born and educated in Austria, Renate sat for the first International Board Exam for Lactation Consultants in 1985 and has been continuously certified and worked in the field since that time. She is currently the Lactation Consultant at The Stamford Hospital, a position she has held since 1997.

Michele Brown, founder of Beauté de Maman, is a board-certified member of the American College of Obstetrics and Gynecology, a member of the American Medical Association, the Fairfield County Medical Association, Yale Obstetrical and Gynecological Society and the Women's Medical Association of Fairfield County. She is a magna cum laude graduate of Tufts University, completed her medical training at George Washington University Medical Center and completed her internship and residency in obstetrics and gynecology at Yale-New Haven Hospital. Dr. Brown has a busy obstetrical practice in Stamford, Connecticut and, as a clinical attending, actively teaches residents from Stamford Hospital and medical students from Columbia Presbyterian Hospital in New York.

Copyright © Michele Brown. Permission to republish granted to Pregnancy.org.