Pros And Cons Of Mixing Breast Milk And Formula – What You Should Know

As a mother to a newborn baby, all you’d want is to keep your baby fed and happy. The thought of your baby crying out of hunger penetrates through your body and crushes your soul. But what if you’re facing troubles with breastfeeding and you want to switch to formula feeding, but you also don’t want to completely formula feed your baby? You want something in between, is there a third option?

When I first wanted to formula feed my baby, so many questions popped into my head. First-time mothers or mothers who have previously exclusively breastfed their other children but now want to do a mixed feed, questions like ‘Can I mix breast milk and formula?’, or ‘Can I supplement breastfeeding with formula feeding?’, or ‘Will I be able to go back to exclusive breastfeeding once I have introduced bottle-feeding?’ tends to pop up.

Yes, you can mix breast milk and formula but with certain conditions kept in mind. You can also supplement breastfeeding with formula feeding, and you can go back to solely breastfeeding after introducing formula feeding.

But, there are major pros and cons with mixing breast milk and formula. Pros include things like you can get a break from continuously breastfeeding your baby; you’ll be able to get more sleep, other family members like the baby’s father or the baby’s caregivers can build a bond with the baby, you’ll be able to go back to work more easily, and such. But with pros comes its negatives too. The major cons for mixing breast milk and formula is the expiration time of the milk. You cannot keep formula milk for more than 1 hour after preparing it. The other cons are, using formula can reduce your milk supply; mixed feedings can take more time, like cleaning the bottles, sterilizing them again and again, and the baby can experience nipple confusion.

Which is best – breast milk or formula?

A mom showing her just made mixture of formula milk for her baby.

To be honest, like anyone else would say, I’d say too that breast milk is best for your baby, as breast milk has a lot of antibodies that protect your baby from falling sick. For babies up to 6 months and beyond, doctors recommend that mothers offer breast milk, and formula is not recommended.

Even for mothers who face issues with low supply, doctors won’t recommend formula, as this can make your supply go down more. Breast milk production works on one condition – the more demand the more supply, meaning more your baby demands milk, and the more your breast is stimulated, the more milk your body will be able to produce.

But for mothers who are facing trouble with breastfeeding might consider formula as their last resort, and let me tell you, there’s nothing wrong with it. At the end of the day, you got to do what you consider is right for your baby and for you. If you think formula feeding is right for your baby, then you do that girl!

I have formula fed my baby, my sister-in-law has formula fed her children, and all of them have grown superbly into healthy children. I know many parents who have chosen formula over breast milk for their kids for many reasons, and all of them are happy with their decision. I think it’s high time mothers are stopped being condemned for what society thinks is the “easy route.”

Can you mix breast milk and formula in the same bottle?

Two bottles of mixed breast milk and formula milk are shown.

Yes, you can mix breast milk and formula in the same bottle, if certain conditions are met.

For example, the storage guidelines for breast milk and formula are different from each other. Breast milk in a bottle can be stored for 3 hours at room temperature, 3 days in the fridge, and 3 months in the freezer.

While formula milk can be kept for 1 hour at room temperature, and you need to dispose of any formula milk left in the bottle within 1 hour of feeding time. You can also make formula milk ahead of time and store it in the fridge for not more than 24 hours.

So, if you mix breast milk and formula in the same bottle, you’ll have to use the bottle within 1 hour of its preparation. This also means that if there’s any milk left in the bottle, it will need to be disposed of, so the ‘liquid gold’ that has taken so much time and effort to pump will be wasted.

Also, mixing breast milk and formula changes the composition of breast milk. Formula milk contains loads of macronutrients, so if used in excess concentration can affect the baby’s kidneys.

Pros of mixing breast milk and formula

Helps with issues like low milk supply

If you’re facing trouble with a low milk supply, and your milk is not sufficient for the baby, then you can supplement your breast milk with some formula.

You can combine pumped breast milk and formula in a bottle and offer it to your baby.

Helps you to easily transition back to work

If you plan to rejoin work, then this can also be a way to feed your baby. Some mothers exclusively feed breast milk by pumping at the office, but in case the expressed milk is not sufficient, you can mix both kinds of milk together.

Helps you to take a break

Neither breastfeeding nor formula feeding is an “easy route”. Both have their advantages and disadvantages. While breastfeeding for some people may seem like not a lot of work, because you just need to plop your breast out and feed your baby. But the truth is that’s not the case at all. Breastfeeding has its cons too like you end up sitting on your bed for hours to feed your baby.

Because, unlike milk which comes out quickly from a bottle, milk from the breast doesn’t come out quickly, and the mother sometimes ends up breastfeeding for 45 minutes to sometimes 2 hours. Breastfeeding mothers often have to excuse themselves in a social gathering to feed their baby or worry about feeding their baby in public.

Mixing formula milk and breast milk in a bottle let you take a break and you can take some time for yourself.

Helps you to sleep better

Exclusive breastfeeding comes with the condition that your baby is going to wake every 2-3 hours and demand milk, and you’ll have to wake every time and feed your baby, which means you’re not going to get a good, long sleep.

With mixing breast milk and formula, your partner or a caregiver can take over for you and feed the baby, while you can get a good amount of sleep time.

Helps caregivers to bond with the baby

When your partner or the baby’s caregiver is bottle-feeding your little one, it can encourage great bonding time between them.

Cons of mixing breast milk and formula

A mom is breast pumping to eventually bottle feed her baby boy.

It can decrease your breast milk supply

It’s easy- the more your baby breastfeeds, the more milk you’ll be able to produce. Human milk production is a demand and supply game. If your little one feeds less, your body will automatically assume that less milk is needed by your baby, and so the milk supply decreases.

If you supplement breast milk with formula, your body is going to end producing very little. Sometimes, new breastfeeding mothers tend to think they have a low milk supply because they don’t feel engorged anymore or their breasts don’t seem heavy like before, or if the baby still cries after a feed which usually happens during a growth spurt. During these times, mothers tend to replace breast milk with formula, resulting in low milk supply in them.

You might waste your ‘liquid gold’

The worst nightmare of any new mother is wasting their breast milk which has taken so much effort and time to be pumped in the first place. There is a possibility that you might waste that ‘liquid gold’ if your baby wasn’t able to finish the bottle, or if you keep the mixture for more than 1 hour at room temperature. At such times, you don’t have any other option than to dispose of it in the drain.

I remember the times I’ve cried when I’ve spilled breast milk from the bottle or it has gone bad because it wasn’t stored properly, and this can make any mother very emotional because we know the hardships and efforts even behind that 1 oz of milk pumped.

Nipple confusion

Another major drawback of mixing breast milk with formula or even bottle feeding is nipple confusion. Sometimes after bottle feeding for a few days or weeks, babies tend to prefer their bottles over the breast.

One of the main reasons for this is because, through the nipple of the bottle, milk can flow out easily in comparison to a human breast.

Mixing breast milk and formula every time takes time

Once you start mixing breast milk and formula, you’ll notice that it takes a very long time to prepare one single bottle. You need to go through the whole process of sterilization, mixing, and cleansing again before and after every feed.

Pumping milk takes time and efforts

Be it hand-expressed milk or milk pumped through an electrical or manual pump takes a lot of time, effort, and patience. Compared to this, breastfeeding can sometimes seem way easier.

The process of pumping can itself take 20 or 30 minutes, and afterward, you’ll need to clean the pump as well all the bottles, and in case you forgot or skipped a pumping session, it can lead to blocked ducts which can be quite painful.


The gist in short of the whole article is yes, you can mix breast milk with formula, but you need to keep the cons in mind too. If you’re still willing to go ahead, then keep in mind the storage guidelines for formula milk.

Prepare the milk when you think your baby is going to be ready. Don’t follow a schedule of feeding every 2 hours, instead wait for when your baby is ready for her next feed and prepare accordingly.

Also, there is another option for you instead of mixing both breast milk and formula is, mixed feeding, which means, breastfeed your baby first and then you can supplement it with formula feeding. Include breastfeeding as much as possible in a day so that you can maintain your milk supply.

Meanwhile, Mamas, hang in there, this is just a phase, and you’ll get to the other end beautifully!

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Located in India and a mother to a joyfully mischievous son, Kelin is the wife of the world’s most patient man and a busy homemaker. When she’s not busy cooking and running after her kid,  you can find her in a corner reading, or penning down words on her laptop. She believes the world will always try to instil ‘mom guilt’ in new mothers, but she goes by the maxim ‘a mother knows best'.

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