Common breastfeeding questions

Breast Milk didn't freeze in the freezer

You’re pumping and throw that bag of liquid gold in the freezer, but when you come back the next day the bag is still liquid. Puzzled, you hit up google only to find no actual answers for why this happened.

HELP! My breast milk won't freeze!!

There is only one research study done in Spanish that has attempted to research this phenomenon. Here’s what we know:

🍷It’s not because you’ve had too much alcohol. Yes, alcohol has a lower freezing temperature, but the amount of alcohol you’d have to consume to get that level in your milk would land you in the hospital

🧊Check to make sure your freezer is at the correct temperature.

🥶The quick fix is to take the bag out of the freezer, shake it vigorously and put it back in the freezer in a single layer without it touching other bags

🍦 There are a few theories about this. One PhD chemist says it has to do with the high osmolarity of that particular milk. Basically it has extra nutrients than other milk, extra vitamins and most likely a higher fat content  it’s why it doesn’t happen all the time

🔬Dr. João Aprigio Guerra de Almeida is Coordinator of the Network of Milk Banks of Brazil and states:

“The fact that human milk does not freeze is associated with a phenomenon called gelation, which is autocatalytic, begins even inside the mammillary ducts, continues after extraction, and is accentuated by temperature fluctuations (heating to thaw, pasteurization and cooling) and does not disqualify the milk for consumption.” Basically, pressure from the ducts changes the protein structure of the milk which prevents the milk from freezing. Even if the milk is kept at -18ºC in the freezer, it does not freeze, because the proteins form a network that ignites the water molecules, preventing them from coming together to form ice crystals.

Have you ever experienced this with your milk?

The discussion by Dr. João Aprigio Guerra de Almeida is translated from Spanish from an original blog post written on December 14, 2018  by Gema Cárcamo González-IBCLC.

SOS, mi leche materna no se congela.

How long is breast milk good for?

I often get asked about the safe handling storage of breast milk as well as formula. So let’s break it down:

Breast milk is a living substance with digestive enzymes that help break down milk in baby;’s digestive tract. It’s also full of live immune properties to help baby fight infections, bacteria and viruses. Formula is FOOD. I know that seems obvious, but it’s really important to remember. Since it is food, we have to follow food safety rules when preparing, using and storing formula. Breast milk is also a food, but like all foods, they have unique storage properties based off of what the food is and the risk of contamination and spoiling. So the rules for formula and breast milk are similar, but different. The rules for formula help prevent bacterial contamination which can make your baby sick. Keep in mind that these are guidelines. You know your home situation best, which includes your water source, what else is living in your refrigerator, the climate you live at, and your own cleanliness in the kitchen. 

Let’s talk about formula first. Prepared formula, meaning mixed powdered formula that you made with water following the manufacturer’s instructions but that has not come into contact with your baby’s mouth, can be stored in the fridge for 24 hours at an ideal temperature of 37 degrees Fahrenheit. CLICK HERE TO LEARN MORE Ready to feed formula that hasn[‘t been offered can actually be stored inthe feridge for up to 48 hours, ideally in an air-tight storage container. This is stored in the back of the fridge where it is coldest and least likely to be impacted by temperature fluctuation that happen near the door of the fridge. This does mean that if you are offering more than one bottle of formula per day you can mix your entire day’s worth of formula in the mourning, store it in a pitcher,and pour out of the pitcher into your bottle volumes to heat and feed. This can save you time when your baby is really hungry. You also want to make sure all of your containers for storage are air tight to prevent that formula from absorbing odors from other foods in the fridge. 

2 hours. That’s how long you have for formula to sit at room temperature once it’s been mixed, as long as it hasn’t touched your baby’s lips. That means you can mix up a bottle before you leave the house and leave it in your diaper bag to be fed within two hours of leaving the house. 

Once that bottle of formula has touched your baby’s lips, you have to use it within 1 hour or you need to toss it. This is because bacteria from your baby;’s mouth is introduced back into the bottle (thanks baby back wash) and the bacteria can multiply and grow to unsafe levels. Health care providers will always recommend safest practice to help keep your little one healthy. 


Worried about wasting formula? Here are a few tips: Mixing formula in a pitcher means you can pour out just enough for the feeding. If baby is still hungry, you can pour small amounts for top ups to prevent mixing too much and wasting formula. If your baby has a little formula remaining in the bottle and you know they will want a top off later, consider offering the bottle again at the 50-minute mark before the bottle expires. 

So what about freshly pumped breast milk? There are other rules that apply:

  • Use breast milk storage bags or clean, food-grade containers to store expressed breast milk. Make sure the containers are made of glass or plastic and have tight fitting lids.
    • Avoid bottles with the recycle symbol number 7, which indicates that the container may be made of a BPA-containing plastic.
  • Never store breast milk in disposable bottle liners or plastic/ziplock bags that are not intended for storing breast milk.
  • Freshly expressed or pumped milk can be stored:
    • At room temperature (77°F or colder) for up to 4 hours.
    • In the back of the refrigerator away from the door for up to 4 days.
    • In the freezer for about 6 months is best; up to 12 months is acceptable. Although freezing keeps food safe almost indefinitely, recommended storage times are important to follow for best quality. Freeze your milk flat to save space and make sure to store int he back of the freezer where it’s coldest, away from the door where temperature can fluctuate.
  • If you don’t think you will use freshly expressed breast milk within 4 days, freeze it right away. This will help to protect the quality of the breast milk. The longer breast milk sits out, the more the live digestive enzymes in it will break down the nutrients in your milk. 
  • When freezing breast milk:
    • Store small amounts to avoid wasting milk that might not be finished. Store in 2 to 4 ounces or the amount offered at one feeding.
    • Leave about one inch of space at the top of the container because breast milk expands as it freezes.
    • Breast milk can be stored in an insulated cooler with frozen ice packs for up to 24 hours when you are traveling. At your destination, use the milk right away, store it in the refrigerator, or freeze it.
  • Make sure to test for lipase before storing large batches of breast milk in the freezer. Lipase is the enzyme that breaks down the fat in breast milk. For some people with high lipase, their milk can taste soapy or metallic when stored. Some babies are fine to drink this milk and others may refuse it. See my other posts and videos on high lipase and what to do about it. 
  • Always thaw the oldest breast milk first. Remember first in, first out. Over time, the nutrients in breast milk start to break down. When at all possible, feed fresh milk. 
  • Breast milk can be defrosted in the fridge, normally in around 12 hours. Alternatively, hold the bottle or bag of frozen milk under warm running water (a maximum of 37 °C or 99 °F). Don’t leave frozen breast milk to defrost at room temperature. If you forget it on the counter for too long, past safe feeding guidelines, you may lose that batch of milk. And we cry over spilt and lost breast milk. 
  • Never thaw or heat breast milk in a microwave. Microwaving can destroy nutrients in breast milk and create hot spots, which can burn baby’s mouth.
  • If you thaw breast milk in the refrigerator, use it within 24 hours. Start counting the 24 hours when the breast milk is completely thawed, not from the time when you took it out of the freezer. If there are still ice crystals felt in the milk, it is still considered frozen.
  • Once breast milk is brought to room temperature or warmed, use it within 2 hours.
  • Never refreeze breast milk after it has thawed.
  • Breast milk does not need to be warmed. It can be served room temperature or cold.
  • If you decide to warm the breast milk, here are some tips:
    • Keep the container sealed.
    • Place the sealed container into a bowl of warm water or hold it under hot, running water for a few minutes.
    • Test the milk’s temperature before feeding it to your baby by putting a few drops on your wrist.
  • Swirl or shake the breast milk to mix the fat, which may have separated. Fat separation is normal for breast milk. There used to be an old wives’ take that shaking the milk could some how damage the milk. We’ve debunked that for years. If you’re concerned about the bubbles that form from shaking giving your baby gas, you can swirl or stir it as well.  
  • If your baby did not finish the bottle, use the leftover milk within 2 hours after the baby is finished feeding. After 2 hours, leftover breast milk should be discarded. Yes, you get a longer amount of time to offer breast milk in a bottle than formula.

Finally: If you’re mixing breast milk and formula together in the same bottle: Formula rules apply, meaning once that bottle has touched baby’s lips, you only have one hour to feed it to the baby. 


Headache while breastfeeding

I have a headache but am also breastfeeding. What can I safely take for me and my baby? Well, first, if you have a headache, start by drinking water. I see many new mothers who are breastfeeding who are not getting adequate nutrition and specifically hydration because of focusing on their little one. If you have a new onset headache, before reaching for the medicine cabinet, start by hydrating. Water, coconut water, soups or births, and High water fruits and vegetables like melon , pineapple, oranges or citrus fruits and cucumber, lettuce, and celery. If that doesn’t do the trick , there are safe medications to take. Dr Thomas Hale wrote the textbook on medication and breastmilk and categorizes them into 5 categories:

L1 safest

L2 safer

L3 probably safe

L4 possibly hazardous

And L5 hazardous.

If you have pain, such as a headache, body aches, pain post delivery or a fever, there are safe medications.CLICK HERE FOR VIDEO

Ibuprofen, Advil, and Motrin are all nonsterioial anti-inflammatory analgesics (NSAIDs), and considered L1 or preferred medications. Panadol, acetaminophen or Tylenol are pain relievers that are considered L1 and safe while breastfeeding. Aspirin, ASA, is considered an L2 medication. While L2 medications are typically considered safe while breastfeeding, Aspirin use  can lead to a condition in babies and children called Reye Syndrome which has been associated with brain and liver damage. Aleve (also known as Naproxen) is considered an L3 and while the AAP-approved it for nursing mothers, Dr Hale states it should be used with caution due to its long half-life and its potential effect on baby’s cardiovascular system, kidneys and GI tract. Use of  Aleve should be short-term, infrequent or occasional use which would still be considered compatible with breastfeeding. 

Ibuprofen or acetaminophen are better choices over aspirin and naproxen for pain relief in lactating women and you would want to discuss the risks and benefits of aspirin If your physician has prescribed this for you based on your unique medical history. 

Codeine is an L3 medication and not generally recommended while breastfeeding. If it is essential, and only where there is no alternative, it should be at the lowest effective dose for the shorted possible duration and you should stop taking it and seek medical attention if you notice side effects in your baby such as breathing problems, lethargy, poor feeding, drowsiness or slow heart beat. 

If you have another medication that you take for fever or pain, you can ask the IBCLC lactation consultant you’re working with to check out it’s safety in the Hale’s Medications and Mother’s Milk textbook, on you can search the LactMed database on the internet. You can also call Infant Risk which is a help center for questions about breastfeeding, infants and medications. If you are in the USA, The phone number for the call center is 1(806) 352-2519 and is open from 8 AM to 5PM Central Standard Time to answer your questions.

I have a sore throat or cough: In general, treat only the symptoms you have, so try to avoid combination medications when one that is for a single symptom could work. Short acting medications that are for less than 4 hours are preferred over longer lasting medications. How you take a medication does matter. Nasal sprays or topical rubs have less of a chance of passing to your breast milk than things you take orally.  

Throat lozenges and sprays are generally considered safe, but avid eating excessive cough drops contains menthol as some have found this can decrease their milk supply. 

Drinking lemon and honey or chamomile tea can be helpful to soother a sore throat and reduce coughing.  Fenugreek tea has also been reported to have a similar effect, although do not drink fenugreek tea if you have a thyroid condition or are on thyroid medications or tend to be hypoglycemic and be aware that it may cause increase gassiness and bloating for you and baby. 

Zinc gluconate or slippery elm bark herbal lozenges may be soothing, but avoid taking large amounts of zinc for more than a week, because it can interfere with other minerals in the body.

Salt water or apple cider vinegar mouth gargles, where you gargle and spit can also bring relief and would not be anticipated to impact milk supply or your baby.

Many forms of robitussin, delsum and benylin are considered compatible with breastfeeding, but always check the active ingredients as there are many versions available on the market. 

Always check with your prescribing physician before starting any herbal supplement or medication based on your unique medical history.