A Guide to Supplementing Breast Milk With Formula

Simply put, supplementing, also known as combination feeding, is providing breast milk plus some formula feeding. There are many reasons why you may choose to supplement and many ways to do it. And, you can decide to supplement at any time during your breast milk-feeding journey. It’s up to you and whatever makes sense for your family and lifestyle.

It’s also possible to alternate between breast milk and formula. Your baby may seem to like breast milk or formula better, but many babies like both equally. However it works best for you, combination feeding is a great way to keep giving your baby the important nutrients in your breast milk.

Common reasons for supplementing breast milk feeding with formula:

• Low breast milk supply
• Going back to work
• Personal choice
• Doctor recommendation
• So your family can help with feeding

There can be an adjustment period when you first introduce formula! Here are a few things to keep in mind when you start supplementing.

You may notice these changes in your baby’s eating habits:

•      Bottle refusal 
  
•      Eating faster
•      Longer times between feedings
•      Less frequent stools    

Your little one may sense something has changed

Your baby associates your smell with breastfeeding, so it might be confusing if you are the one who gives them formula for the first time. Some moms find that the first bottle-feeding goes more smoothly if they aren’t nearby. If your baby senses your presence, they may be less likely to take the bottle and expect to be breastfed.

They eat faster from a bottle than from your breast

Some parents are surprised at how quickly their baby eats from a bottle. This is because your baby can better regulate the pace of feeding from the breast, compared to bottle-feeding.  Even though your baby may be eating faster, it's not always a sign that they are hungry for more.

Help your baby to burp midway through the feeding, if possible, and definitely afterwards. This will help relieve pressure from swallowed air that can build up in your baby’s stomach.

Baby can go longer between feedings without getting hungry

Formula takes longer to digest than breast milk. This means your baby may feel full longer, and you may notice them feeding less often. Regular feedings are still important, though. Waiting too long could affect your baby’s health or leave them feeling hungry.

Here’s an easy way to keep a record of feedings: Download and print our baby Feeding Tracker(PDF, 24.3 MB)

Stools might be firmer and have a stronger odor

Any time you change your baby’s diet, you may notice a change in stools. When you add formula or baby foods to your baby’s diet, you may notice your little one’s stools become firmer and change in odor, color, or consistency.

If you have additional questions about your baby's health after you begin supplementing formula while breastfeeding, contact your pediatrician for more support.

Our Diaper Decoder can also help you answer questions about your baby’s stools.

Babies may have different needs when it comes to how often and how much they eat. Follow your baby’s lead. The same hunger cues that you use when breastfeeding also apply to your baby when you offer a bottle.  Here are some things to look for:

Follow your baby’s lead

• Feed when your baby wants to eat
• Pay attention to hunger cues—rooting for milk, sucking motions, or putting hands to mouth
• Crying can be a late sign of hunger

Measure amounts of breast milk and formula

If you are already bottle-feeding pumped breast milk to your baby, you should have a good idea of how many ounces of formula they will eat at one time. If you are only breastfeeding, it’s hard to be sure.

As you begin feeding your baby, they will give you cues to let you know if they are getting enough to keep them full. As your baby gets older, you may find that they are able to eat less often and eat more at each feeding.

To see Similac^® formula feeding guidelines for babies from 1 week to 1 year old, download our baby Feeding Tracker(PDF, 24.3 MB).

Tip: Try Similac^® 360 Total Care^® Ready-to-Feed baby formula. It requires no mixing and comes in premeasured 2-fl-oz and 8-fl-oz bottles.

Count the wet diapers

You can also tell whether baby is getting enough food by counting how many diapers you change each day. Six to 8 wet diapers and 1 or 2 passed stools per day is common for babies fed formula. Contact your baby’s doctor if you have concerns about your baby’s eating or digestion.

Your baby's weight gain

If you are feeding your baby enough, they will also gain a small amount of weight each week. Babies gain weight and develop at different rates, so consult your doctor if you have questions about your baby’s weight gain.

Similac offers a wide variety of infant formulas that can be used to supplement breastfed babies. Similac 360 Total Care is a great option. Similac Pro-Total Comfort^® and Similac^® 360 Total Care^® Sensitive are also good choices. 

Similac also offers formulas that are soy-based or for lactose sensitivity to support your baby's nutrition when they experience:

• Frequent fussiness and gas
• Colic due to protein sensitivity
• Frequent spit-up

Some of our products also have our exclusive blend of DHA, lutein, and vitamin E. These ingredients help support your baby's brain and eye development.

Check with your pediatrician for the best formula for your baby. Also, the Similac Formula Finder can help you find formula choices.

If your milk supply seems low at first, there are things you can try to get things going again. For moms who are currently breastfeeding, continued breastfeeding—along with pumping between feedings—will encourage your body to make more milk.

Some babies seem to prefer the bottle to breastfeeding. If this applies to your baby, try breastfeeding when they are very relaxed or sleepy, just before a nap, at bedtime, or during a nighttime feeding. You can also encourage breastfeeding through more skin-to-skin contact.

For more helpful advice, see our guide to Breastfeeding Basics article.