Can you mix formula and breastmilk?

Breast milk is the perfect food for your baby. It is complete nutrition for the baby for the first six months of life. But sometimes, you might need to feed them formula.

You may be away from your baby or not making enough milk. Know that feeding formula along with breast milk is OK. It’s called combo feeding.

But there are pros and cons of mixing breast milk and formula. There are also some important safety rules. Keep reading to learn how to combo feed breast milk with formula.

Can You Mix Formula and Breast Milk?

Doctors agree that breastfeeding is the best source of nutrition for at least the first six months of your baby’s life. In a perfect world, you would feed your baby breast milk for two years. In the real world, that’s not always possible.

Sometimes you must add to your breast milk with formula. You may need to feed formula because of your schedule or milk supply.

The good news is that feeding your baby breast both milk and formula is safe. In some cases, it’s the best option.

There are a few ways to combo feed:

  • Go back and forth between breastfeeding and formula bottles.
  • Pump your milk and go back and forth between bottles of milk and formula.
  • Mix your pumped milk with formula in the same bottle.

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Why Mix Formula and Breast Milk?

You might want to combo feed for many reasons. Reasons might include any of the following.

  • You’re not making enough milk. Certain health issues, medications, or previous breast surgery can reduce milk supply. If your baby isn’t getting enough, your doctor might suggest adding formula to their diet.
  • You’re feeding more than one baby. Feeding multiple babies requires a lot of milk, which is hard to maintain. It also leaves you feeling exhausted and in need of extra rest. Swapping breastfeeding with a bottle of formula can help.
  • You’re returning to work. Maybe your schedule doesn’t allow for breastfeeding or pumping during work hours. Or you’re traveling for extended periods and can’t afford to ship your breast milk.

No matter your situation, feeding your baby some formula enables you to breastfeed part-time. You can breastfeed your baby when you’re at home. While you’re away, your baby can have formula or pumped breast milk mixed with formula.

Feeding bottles of formula lets your partner help more. Sharing your baby’s feedings gives you a much-needed break. It also gives your partner bonding time with the baby.

Making adequate breast milk and feeding your baby every few hours is hard work. It’s easy to become exhausted, and sometimes you may need a break from breastfeeding.

If you decide to take a break, you should never feel guilty. It is normal to need an occasional break to rest and care for yourself.

How Should You Mix Breast Milk and Formula?

There are a few different ways to mix breast milk and formula.

One way is to switch feedings between breast milk and formula. This allows your baby to wean from breastfeeding slowly. It also lets your partner or support person take some feedings.

You can also mix pumped breast milk with formula in the same bottle.

If you’re using a liquid-prepared formula, pour it into the bottle with your breast milk.

If you’re using a powdered formula, measure it and the water as directed on the label. Then prepare the formula according to the directions. Once you prepare the formula, mix it with any amount of breast milk.

Are There Any Safety Concerns When Mixing Breast Milk and Formula?

When your baby feeds from your breast, you never have to worry about preparing, storing, or keeping your milk fresh. But there are many food safety issues with formula, pumped milk, and combo feeding.

To be safe, keep these steps in mind:

  • Check the formula label and never use a formula past its “use by” date.
  • Clean and sterilize bottles, pump parts, and other supplies before preparing anything. This prevents bacterial growth, which can be harmful to the baby.
  • Make formula using properly measured amounts. Never use breast milk instead of water when preparing powdered formula. Doing so could harm your baby.

How Should Formula and Breast Milk Be Stored?

Keep these storage guidelines handy to help keep your formula and breast milk safe:

  • Prepared formula can be safely refrigerated for up to 24 hours. If it’s at room temperature, use it within two hours.
  • Freshly pumped breast milk can be safely refrigerated for four days. If it’s stored in the freezer, it’s good for six months. If it’s at room temperature, use it within four hours.
  • Formula mixed with breast milk can be safely refrigerated for up to 24 hours. At room temperature, use it within two hours.

Throw away any bottle you’ve started feeding your baby with an hour after it touches their mouth.

What are the Pros and Cons of Mixing Breast Milk and Formula?

Mixing breast milk and formula can help boost your baby’s calories and nutrition. It may also fill their stomach for longer. This may let you stretch the time between feedings.

Adding some formula to their breast milk at night helps give you more sleep.

But your breast milk supply may drop once you add formula to your baby’s diet. Breastfeeding works on a supply-and-demand basis. The more your baby breastfeeds, the more you’ll produce. If you feed your baby less breast milk less often, your body will slowly make less milk.

Talk to your doctor or a lactation consultant before you start combo feeding. They can provide tips to help keep your milk supply up. If you have a newborn, they may suggest only breastfeeding for at least a month to establish a good supply.

Another potential downside to mixing formula and breast milk is the potential for waste. It’s hard to know whether your baby will finish an entire mixed bottle.

To avoid waste, start by feeding breast milk alone. When they’re done, offer some formula if they still seem hungry.

Remember: You don’t have to choose between exclusively breastfeeding or formula feeding.

Even small amounts of breast milk benefit your baby. Sometimes mixing breast milk and formula works best for you and your family, and that’s OK.

Talk to your health care team if you have questions or concerns about feeding your baby. They want what’s best for your baby, just as you do.

Editor's Note: This article was originally published on , and was last reviewed on .

Centers for Disease Control and Prevention. Infant Formula Preparation and Storage. LINK

Centers for Disease Control and Prevention. Proper Storage and Preparation of Breast Milk. LINK

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