Can I pump breast milk into the same bottle all day

Can I Pump Breast Milk Into The Same Bottle All Day?

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Most new mom asks this question often – “Can I Pump Breast Milk Into The Same Bottle All Day? The answer is Yes, breast milk can be pumped into the same bottle over the course of a day. However, a few guidelines must be met due to its popularity among parents especially working parents. It affords parents a chance to continue in their career path while ensuring that their babies are getting the best nutrition.

Therefore, pumping is about more than just expressing the milk, it is about making sure that it is properly stored and that it remains viable and healthy during storage. To shed more light on the question “Can I Pump Breast Milk Into The Same Bottle All Day?”, we will discuss ways to collect milk pumped over the course of the day, keeping accessories clean, the viability of milk, and factors affecting viability.

Tips on Storing newly expressed milk

What you must consider, is the temperature. Experts have shown that putting warm milk in cold milk can lead to the growth of bacteria. Over the course of the day, you may need to add fresh milk to the following:

How To Add Fresh Milk To Frozen Milk

According to guidelines, adding fresh milk to frozen milk directly is not safe for your baby, hence a process called layering. Layering involves putting the fresh milk in a refrigerator to make it cold and also bringing the frozen milk into the refrigerator to bring it to that temperature. Then add the fresh milk to the frozen milk as long as both batches of milk were pumped the same day.

How To Add Fresh Milk To Defrosted Milk

It is important to know that fresh milk is more beneficial than defrosted milk. So although it is not wrong to add fresh milk to it, it is better to feed your baby the fresh milk first and then continue feeding him with the defrosted one. That way, if there are any leftovers, it would be the defrosted milk which you should throw away and not refreeze.

How To Add Fresh Milk To Refrigerated Milk

To do this, you must first bring the fresh milk into the refrigerator to cool it down for an hour or thirty minutes. Thereafter, you can now add fresh milk to the older one.

How To Add Fresh Milk To Milk At Room Temperature

You can add your fresh milk to room temperature milk with no issue. This usually happens when you are in the process of pumping milk and you have some on your counter which was expressed first.

Know that in all the above scenarios, the fresh milk will be dated according to the first milk in that bottle. This means that if the first milk in the bottle was pumped 2 hours ago, then the fresh milk added is now 2 hours old.


Milk can be exposed to contamination not just during storage but at the point of expression. These tips will help to reduce that risk:

  1. Clean all pumping accessories in a clean basin with soap and water rather than in the sink.
  2. Sterilize the accessories in boiling water, microwave, or dishwasher.
  3. Ensure that the accessories are neither too tight or too loose around the nipple.
  4. Collect the milk in a sterilized bottle and refrigerate immediately.
  5. Write the date and time each milk was collected on the container and use older milk first.
  6. After thawing frozen milk, shake properly to distribute the fat by rubbing between the palms.
  7. Always discard unused portions of thawed milk, not refreeze.
  8. All containers should hold milk pumped on the same day.
  9. Never add fresh milk directly to refrigerated milk without cooling first.
  10. When collecting milk for donation, follow the hospital and milk bank guidelines. Also, if it is for a sick baby, the milk should be sealed after pumping and only opened again for consumption.


  1. Freshly pumped breast milk remains just fine at room temperature for up to six hours. Nevertheless, it’s better to use breast milk or properly store it within four hours.
  2. In a cooler: Fresh breast milk can be stored in a cooler with ice packs for up to 24 hours.
  3. In a Refrigerator: Your fresh milk should be stored at the back of the refrigerator and not in the door. It remains viable for five to eight days but should be used or frozen in three days.
  4. In a Deep freezer: The deep freezer is the most ideal storage unit for your breast milk. It is best to use fresh milk within six months of its storage in a freezer. However, fresh milk stored at the back of the freezer lasts for up to twelve months.

This is summarized in the Rule Of Six which concludes that breast milk is at its best within 6 hours of being on the counter, 6 days in the refrigerator, and 6 months in the freezer.

It is also better to use stored milk quickly because research has shown that the longer breast milk is stored, regardless of the conditions of storage, the higher the loss of vitamin C in the milk. Changing storage conditions does not really buy you time, the milk will still spoil faster in the new storage medium than if it had been kept there, to begin with.


1. Temperature:

Milk should be the at stored back of the freezer or refrigerator which is the coldest part where it can be least affected by the opening and closing of the door

2. The Storage Bottle:  

Breast milk should be stored in hard plastic, glass bottles, or non-BFA bags. They should be well sealed after milk collection to avoid spoilage and refrigerated or frozen immediately.

As seen from the discussion above, the answer to the popular question “Can I Pump Breast Milk Into The Same Bottle All Day – is yes. These above tips and guidelines will help to ensure that your baby gets the safest milk at all times. Always recall that breast milk is most beneficial to your baby immediately after pumping, use the older milk first before the later ones, do not mix milk which was pumped on different days, do not refreeze defrosted milk, keep pumping accessories clean and use the best accessories at all times.

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