Combining Breastfeeding and Formula Feeding

Supplementing can ensure adequate nutrition and ease feeding challenges

Giving your baby formula in addition to breastfeeding is called supplementing. It's completely OK and perfectly safe to do, and many families choose this type of combination feeding method, whether out of necessity (e.g., low breast milk supply), convenience, or simply a personal choice. In some cases, breastfeeding and providing formula may be recommended by a doctor for medical reasons.

Reasons to Supplement Breast Milk With Formula
Verywell / Brianna Gilmartin

Reasons for Supplementing With Formula

The American Academy of Pediatrics (AAP) and the World Health Organization (WHO) recommend breastfeeding exclusively for the first four to six months and then continuing to breastfeed up until one year or longer, along with the introduction of solid food.

For this and other reasons, including emotions and cost, making the decision to supplement with formula may not be an easy one. While many moms breastfeed their babies and give them formula because they want to, others do so because they simply have to.

The following are some reasons that might prompt you to supplement breastfeeding with formula feedings. Regardless of whether all or none of these apply to you, remember that the decision is entirely up to you.

Your Child Has Medical Issues

If your baby is born premature or with certain medical conditions, she may need more than just your breast milk. Supplementing is often done for the purpose of helping a baby gain weight.

You Have a Low Breast Milk Supply

A previous breast surgery or certain medical conditions can interfere with the production of breast milk, though any woman can experience low supply. If you or your doctor feel that your baby is not getting enough breast milk through breastfeeding alone, you may need to supplement with infant formula.

You're Going Back to Work

It may be too difficult or stressful to pump at work, or you may have a decrease in your breast milk supply once you return to work. If you don't have a stockpile of breast milk stored in the freezer, you may have to supplement your baby's diet with formula.

Your Partner Wants to Participate

Your partner may want to take part in feedings (and you might welcome sharing the responsibility too). You could pump and use your breast milk, or you can give your little one a bottle of formula once in a while.

You Have Multiples

Exclusively breastfeeding twins or triplets can be a challenge. Not only do you have to build and maintain a large enough breast milk supply, but you'll be breastfeeding very often. You may just need a break a few times a day (both physically and mentally), and formula feedings can help with that.

You Just Want To

You may just have a personal preference to breastfeed some of the time and give your baby formula the rest of the time.

When Doctors Recommend Supplementation

When possible, most doctors recommend exclusive breastfeeding. However, there are certain times when it's necessary for a physician to recommend supplementing a breastfed baby.

Your doctor may recommend formula supplementation if:

  • Your newborn loses more than 10 percent of his or her body weight in the first few days of life
  • Your child loses weight or gains weight slowly after the first few days
  • Your baby is having less than six wet diapers in a 24-hour period
  • Your newborn is very fussy and does not seem satisfied after feeding

Introducing Formula

If you're not supplementing your child for medical reasons, experts recommend breastfeeding for at least one month before starting formula.

Waiting at least four weeks gives you time to build up a healthy breast milk supply and ensure that your baby is breastfeeding well. At this point, you can slowly begin to add formula.

Before choosing an infant formula for your child, talk to the pediatrician. Most doctors recommend an iron-fortified infant formula during the first year of life.

If your baby develops a rash, vomiting, diarrhea, excessive crying, fussiness, or gas after starting formula, it may be an allergy. Stop using the formula and notify the baby's doctor to discuss other types of infant formula available.

Supplementing will be a change for you both if you've been exclusively breastfeeding. These strategies can help with the transition:

Feed Breast Milk and Formula Separately

While is OK to put breast milk and formula in the same bottle if you have already prepared the formula, mixing them can lead to wasted breast milk if your baby does not finish the bottle. If possible, give your breast milk first, then finish the feeding with the infant formula.

For safety reasons, you should never combine your breast milk with unmixed powdered or concentrated formula.

Start With One or Two Formula Bottles a Day

Each day, your body makes breast milk based on the concept of supply and demand. So, when you start to add the formula, it can affect how much breast milk you make. If you plan on supplementing one or two bottles a week, it shouldn't affect your breast milk supply. But, if you give your child one or two bottles of formula a day, your milk supply will begin to drop.

Add More Formula Bottles Slowly

Going from not supplementing to giving a lot of bottles in a short period could cause breast problems such as breast engorgement and blocked milk ducts. It may also cause your child gastrointestinal issues (see below).

Consider Pumping or Hand Expressing

Either can help keep up your breast milk supply and prevent some of the common breastfeeding problems that can pop up when you skip nursing to bottle feed. Removing your breast milk will help relieve the fullness that breast engorgement can cause. Plus, you can store your pumped breast milk to use at a later time. Depending on how you store it, breast milk can stay in the freezer for up to one year.

How Adding Formula Affects Your Baby

If you've been breastfeeding your baby and begin to add formula to her daily diet, there are some things you may start to notice.

Refusing the Bottle

Your child may refuse to take the bottle especially if you're the one giving it to him or her. The transition may go more smoothly if you have your partner or another caregiver offer the formula.

Aside from simply wanting milk from Mom, some babies may have a hard time getting the hang of using a bottle. Others may just not like the taste of the formula.

Waiting Longer Between Feedings

Since your baby can digest breast milk more easily than infant formula, the latter allows her to feel fuller longer. She may not seem as hungry as quickly after formula feedings as she does after breastfeeding.

Refusing the Breast

Refusing the bottle is usually no longer an issue after some time. After your child gets used to the formula and drinking from a bottle, however, you may have the reverse issue: She no longer wants to nurse. Drinking from the breast takes more work, and many babies end up finding formula more satisfying.

Changes in Bowel Movements

Adding a formula to your baby's diet may change the pattern, color, and consistency of your baby's poop (it may be firmer, tan or darker in color, and have a stronger odor than before). Your child may also poop less often once you start giving him the formula.

A Word From Verywell

The ultimate goal of every parent is to have a happy, healthy baby who is growing and thriving. It is great if you can breastfeed exclusively, but it's not always possible or desirable for every mom. Breastfeeding doesn't have to be all or nothing. Every baby and situation is unique, and a combination of breastfeeding and formula may work best for your family.

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Article Sources

  1. National Institute of Child Health and Human Development. What are the recommendations for breastfeeding?

  2. Johns Hopkins Medicine. Managing Poor Weight Gain in Your Breastfed Infant.

  3. KidsHealth. Feeding Your Newborn.

  4. KidsHealth. Your Newborn's Growth.

  5. KidsHealth. Breastfeeding FAQs: Solids and Supplementing.

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

Additional Reading