New mothers are typically only presented with two options when it comes to feeding their babies: breastfeeding or bottle feeding. But it can be eye-opening to realize that there’s a third option: combination feeding.

Combination feeding involves feeding your baby a combination of both breast milk and formula, sometimes even in the same bottle.

Combination feeding usually involves a period of experimenting and learning—mostly about your baby. After some trial and error, you will determine exactly how much milk your baby needs every day, their favorite bottle and nipple type, and what feeding schedule works best for your family.

All three feeding options (breast, bottle and combination feeding) are good choices. The best choice? The one that works best for you and your baby.

Here are the answers to some of your commonly asked questions about combination feeding.

mom breastfeeding a baby using a boppy

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How do I do combination feeding?

According to the Centers for Disease Control and Prevention (CDC), 1 in 4 breastfeeding mothers in the U.S. supplements breast milk with formula by the time her baby reaches 6 months of age.

Combination feeding is all about finding the right balance between breastfeeding and bottle feeding using pumped milk or formula. This is going to vary by baby and by family, based on your specific variables. Here are a few example scenarios:

  • A mother works outside of the home full-time. When she is away, her baby gets formula from a bottle and when she is home, the baby breastfeeds; it works out to be a 50-50 split between breast and bottle-feeding.
  • A mother mostly breastfeeds, but when she runs errands or takes care of other children or relatives, her partner gives the baby a bottle of formula.
  • A mother mostly bottle-feeds but still nurses her baby to sleep every night.

There are many ways to do combination feeding. The beauty is that you get to decide what works best for you.

As you start experimenting and getting more experience feeding your baby, it will get easier to figure out what balance of bottle-feeding and breastfeeding you and your baby need.

Related: AAP recommends breastfeeding for at least 2 years. Here’s how to make that happen

How much milk does my baby need?

Figuring out how much bottled milk to give your baby requires a bit of math. The average 1- to 3-month-old baby consumes 25 ounces of milk per day over eight to 12 feedings, so start with that and adjust as you get to know your baby.

So, say your baby eats 10 times per day: Dividing 25 ounces by 10 feedings is 2.5 ounces per feeding, so each of the bottles would be about 2.5 ounces.

When you nurse, there’s no need to track how much they get. Here’s how your baby will let you know that they are done breastfeeding:

  • Falling asleep at the breast and staying asleep when you take the nipple out of their mouth
  • Declining to re-latch
  • Showing open, relaxed hands. Look at your baby’s hands when they are done nursing. If they are clenched into fists they are likely still hungry, but if they are relaxed and open, they are likely full.

For week-by-week feeding guidelines, check Motherly’s baby feeding schedule. Remember, every baby is different. For specific recommendations for your baby, check with your pediatrician.

Related: 14 science-backed ways to reduce SIDS risk in babies

When do I start bottle-feeding?

When introducing a bottle to your baby, there seems to be a golden window between four and six weeks. Some experts say that offering a bottle earlier than four weeks can cause nipple confusion, which may result in babies starting to prefer the bottle over the breast because drinking from a bottle is easier.

It’s worth noting that for cases when bottle feeding needs to be introduced earlier, some lactation consultants recommend using special newborn slow-flow nipples anytime you bottle-feed (what’s known as paced bottle feeding)—even beyond the newborn phase—to restrict the flow of milk so that babies need to exert a similar level of effort for both bottle and breast.

Related: The best bottles for breastfed babies

Also, you don’t want to wait too long before giving that first bottle. Introducing a bottle later than six weeks risks having the baby refuse the bottle because they have grown fond of breastfeeding.

When you do give the first bottle, if possible, ask your partner or a friend to feed your baby their first bottle. They are more likely to take it if they don’t think mama is around to feed them.

How do I get started with pumping?

If you’re choosing to supplement bottle-feeding but still want to use your own milk, pumping breast milk is a good option.

When you pump, you have the option to do both breasts at the same time or one breast at a time. What you choose will likely depend on why you are pumping and when you last fed your baby.

For example, if you will be away from the baby for a period of time and are pumping to maintain your supply and bring milk home, you will probably choose to pump both breasts. If you are home with the baby and they have just nursed on the left side only, you may choose to then pump the right side to increase your supply or to add some milk to your freezer stash. You might have success with a milk collection device such as the Haakaa, which uses suction power to collect milk from the breast you’re not currently feeding on. It’s an easy way to start a milk stash without adding another separate pumping session.

Related: Exclusively pumping is still breastfeeding, mama—and here are 5 ways to make it easier

If you’re using an electric or manual pump, be sure to consult your pump’s instruction materials to confirm that you’re operating the breast pump correctly and that the flanges are optimally positioned for you. If you’re feeling pain while pumping, you might need to adjust the settings or flanges size—a lactation consultant can help troubleshoot.

When you’re done pumping, follow the manufacturer’s instructions for cleaning the pump and accessories. If your baby is younger than 3 months old or has specific health concerns, your baby’s provider may advise sterilizing the equipment between uses, so be sure to ask.

How often you pump will depend on why you are pumping, so there will be a lot of variation here. The most important thing to know, though, if you want to maintain your milk supply, is to try to pump as frequently as your baby eats.

Breast milk is made on a supply-and-demand system, so the more you pump, the more milk you will make.

If you will be exclusively pumping, or away from your baby for a period of time, pump as frequently as the baby eats—about every two to three hours. This will maintain your supply and help prevent clogs and engorgement, which can lead to mastitis, a painful infection that may require antibiotic support.

If you are pumping once per day to increase your freezer stash, you might try to pump in the morning, as many moms find that they have the most milk early in the day.

Mamas who exclusively pump will generate anywhere from 19 to 30 ounces of milk per day (though this can vary a lot). If you pump eight times per day, you can expect anywhere from 2.5 to 3.75 ounces per pumping session (and again, your own amounts may be different).

Related: A parent’s guide to car seat safety: Tips, rules & product picks

How do I store breast milk?

If you are going to give your pumped milk to your baby within the next three to six days, you can simply keep it in the fridge. If you plan to store it longer, you can freeze it. In cases where you plan to store the breast milk for later, it’s recommended that you refrigerate or freeze the milk immediately after pumping to ensure maximum freshness down the road.

Here’s how long pumped milk can be stored, according to the CDC:

  • Room temperature: 4 hours. Keep covered.
  • Cooler bag: 24 hours. Keep ice packs in contact with milk, and avoid opening the cooler.
  • Refrigerator: 4 days. Store in the back of the fridge. Clean hands, pump and pumping surface will increase shelf life.
  • Freezer inside refrigerator: 2 weeks. Store in back, away from sides.
  • Separate freezer: Up to 6 months, but 12 months is acceptable. Store in back, away from sides.
  • Deep freezer: 6 to 12 months. Store in back, away from sides.

How do I start feeding with formula?

If you need to formula feed, do so with confidence. Formulas are designed to mimic breast milk and are highly regulated, so they are perfectly safe and healthy for your baby.

There are tons of options out there. Some moms choose organic baby formulas, as they want to be extra careful about pesticides. Your pediatrician can give you guidance on what the best formula for your baby is.

Once a bottle of formula has been prepared, it should be stored in the refrigerator and used within 24 hours. Once the baby has eaten from the bottle, though, it should be discarded within 2 hours.

Can I combine breast milk with formula in the same bottle?

It’s OK to combine breast milk and formula in the same bottle—it doesn’t have to be one or the other.

There are a few reasons a mother might choose to do this: to increase the milk volume of a feed or to stretch out her supply of pumped milk over a few feedings.

When you combine pumped milk and formula in a bottle, don’t worry about the ratio—just combine as much of each as you have, up to the total number of ounces you’re going to feed your baby (see ounce guidelines above). There’s no magic formula for how much of each.

When preparing the bottle, make the formula first and then add in the breast milk. Breast milk should not be used instead of the water used to make formula—this can cause dangerous health problems for the baby.

One last note: Once pumped milk has been mixed with formula, it must be used within 24 hours, or within an hour after the baby has started drinking from the bottle—bacteria enters the bottle as the baby eats and can make the milk start to turn if left for too long.

While it’s fine to combine breast milk and formula in the same bottle, La Leche League recommends keeping them separate for this purpose. “… mixing breastmilk and formula can result in breastmilk being wasted, if the baby does not finish the milk [since the formula needs to be discarded]. Giving your pumped milk to your baby first, and on its own, ensures that all of your “liquid gold” will be used and less will be wasted,” the organization states.

It may take a period of experimenting to figure out exactly what’s right for you and your baby, and that’s OK. As with all areas of parenting, feeding your baby can be highly complex. Ultimately, trust your instincts. Your baby will be fine because they have you—that’s what matters most.

For mamas who are using combination feeding, these are our favorite products to make nourishing your baby a breeze:

Baby Bottle Complete Feeding Set
$49.99

1. Baby Bottle Complete Feeding Set

Nanobébé is the only line that’s totally up to the task of combo feeding. This Complete Feeding Set includes all that you need for bottle-feeding from newborn days through early toddlerhood—along with a natural, mom-like feel that will make the move from breast to bottle easy on everyone. (Also easy on everyone? These bottles are super simple to clean and sanitize!)

dr-browns-option-plus-bottle
$22.63 for a 4-pack

2. Dr. Brown's Options+

Dr. Brown’s wide-neck design has long been a favorite of breastfed babies and championed for their efficacy in aiding digestion and preventing colic & gas. These bottles are also popular among parents who combination feed as they are one of the best choices to avoid nipple confusion.

tommee tippee closer to nature
$39.98

3. Tommee Tippee Closer to Nature

With a super-sensitive bottle nipple that feels like Mom’s, the Tommee Tippee Closer to Nature Bottles have earned a 5-star review from hundreds parents on Amazon. Designed to foster an easy transition from the breast to bottle and back again, the bottles also have anti-colic venting and wide necks that make them a breeze to clean. Easily swap out the nipples to give your baby the optimal milk flow.

Dr. Brown's formula mixing pitcher
$9.97

4. Dr. Brown's Formula Mixing Pitcher

Dr. Brown’s formula mixing pitcher mixes formula in mere seconds. And, because it’s a 32 oz. vessel, you can make multiple servings at once, vs. just one bottle at a time. Extra bonus—even though it conveniently can make multiple bottles at once, it’s still petite enough to fit in your bag for when you are traveling with baby.

willow wearable breast pump
$499

5. Willow Wearable Breast Pump

The revolutionary Willow Generation 3 wearable breast pump is the ideal investment for the combo-feeding mom. With a new app that includes step-by-step on-boarding and simple, fast pairing to your phone, plus volume tracking, session history, and personalized pumping tips, the Willow is meant to make your breastfeeding life easier and more manageable.

Babeyer Breastmilk Storage Tote
$22.98

6. Babeyer Breastmilk Cooler Bag

If you’re a combo-feeding mom, chances are you are pumping and carting breastmilk around with you. That means you’ll need a cooler to keep that liquid gold fresh and protected, and this one from Babeyer will do the job perfectly.

Whether you’re expecting in months or mere days, let Motherly guide you with our registry featuring curated collections of essentials for you and baby.

A version of this article was published August 17, 2020. It has been updated.