What Happens if My Baby Drank Spoiled Breast Milk?

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Written by Amy Kaczor RDN

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Did you notice a change in the smell of your breast milk that has been stored after your baby has already had some? Then, let’s talk about what to do if your baby drinks potentially spoiled breast milk.

Overall, if your baby drank spoiled breast milk, they will most likely spit out the milk immediately. However, they can also vomit the milk up, and then the vomiting should stop. 

In this article, we will cover how to determine if your breast milk has gone bad, as well as the symptoms and common signs to look out for in your baby. Read on! 

My Baby Drank Spoiled Milk – What Should I Do?

If you notice that your baby has drank spoiled breast milk, it is essential not to panic or worry too much. This situation can happen to any parent, and you should be alert of any signs or symptoms in your baby after drinking the milk — more on this below.

breast milk in a bottle and a manual breast pump

Spoiled breast milk often has a sour smell or is rancid and should not be given to your baby (source: La Leche League International). This can occur due to chemical oxidation, which changes the composition of your normal breast milk.

Besides ensuring you store your breast milk safely and appropriately, whether in the fridge, freezer, or a cooler storage bag, there are dietary causes that can increase chemical oxidation in it. Avoid foods high in poly-unsaturated fats, as these fats in foods are more likely to become rancid, such as brazil nuts, fish oil, anchovies, and flax seed supplements.

Additionally, try changing your water source or drinking bottled water because iron and copper ions could cause oxidation. Finally, increase your antioxidant consumption, such as in fruits and vegetables, to help prevent the oxidation.

However, if you notice a soapy or fishy smell, the milk is not spoiled, and it is, therefore, safe for your baby (source: La Leche League International). 

Symptoms and Signs After Baby Drank Old Breast Milk

As mentioned above, it is important not to panic if you realize that your baby has consumed spoiled breast milk. If your baby has already consumed a small amount of it, they will likely spit the milk out immediately because of the unpleasant bad taste. They may also squirm around after drinking it.

a baby vomiting after drinking milk

It is unlikely to cause them any significant harm beyond vomiting shortly after drinking the milk or spitting it out.

However, if you notice any other unusual additional symptoms or the vomiting does not resolve, make sure to contact your baby’s physician immediately. Additionally, contact a health professional if your baby drank a large amount of spoiled breast milk. 

The main risk of vomiting is dehydration. If you notice your baby is urinating less frequently, has very dark-colored urine, or has no tears, seek medical attention right away (source: Seattle Children’s Hospital). 

In conclusion, if your baby drank a small amount of old breast milk and spit it out or vomited it back up, they are likely OK once the vomiting resolves. I hope this article helped explain the nature of spoiled breast milk and instructed you on which signs and common symptoms to monitor.