Whether to breastfeed or bottle-feed is a personal decision for new moms. But sometimes the right choice is to do a combination of the two. When you supplement breast milk with formula, it simply means that you’re choosing to give your baby both formula and breast milk (whether by directly nursing, or bottle-feeding with milk you’ve pumped).
You might supplement because your milk supply is low, your baby has a weak latch or you're heading back to work and won't be able to pump much. You might also decide that exclusively breastfeeding is a lot to take on.
But whether you’ve already started to supplement with formula or you’re considering it, you might be wondering how to maintain your milk supply during the process.[1] If you have questions, you can always ask your baby’s doctor about how often your little one needs formula[2] and which kind of infant formula is best for your baby.
To make sure your milk supply stays on an even keel, here’s what you need to know about each supplementing scenario. Once you’ve nailed down one that works for your family, you might feel the way many women do about combo feeding: It can be the best of both worlds.
Tips on supplementing with formula without impacting your breast milk supply
After you’ve chosen a formula,[3] you can begin supplementing in the same way you’ve been nursing (if that’s been going fairly smoothly), though your best bet is to establish a solid breastfeeding routine first if possible and hold off on the formula option until baby is 3 weeks to 6 weeks old.
Switch sides just as you would at the breast, burp in between each side session, and cuddle your baby closely, looking into her eyes and offering skin-to-skin contact.
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As you offer bottles in between nursing sessions, remember that breastfeeding works on a supply-and-demand system. If you feed your baby your breast milk, your body gets the signal to make more. But if you’re lactating but not breastfeeding (or not nursing as much, anyway), the body reacts by slowing down milk production.
Taking a moderate approach can keep your milk supply up if you’re trying to continue breastfeeding, and it can help prevent a clogged milk duct or breast infection like mastitis if you drop nursing sessions.
Remember, each woman’s breast milk production is a little different. It’s best to make the transition to combo feeding from pure breastfeeding slowly if you’re able to, first introducing a formula bottle an hour or two after a breastfeeding session (when baby’s hungry, not starving) and then gradually building up to more frequent bottle feedings depending on how much formula you want to add to the mix.
Still, for the most part, the following are the typical scenarios that moms tend to encounter as they supplement with formula:
Supplementing with formula with an oversupply
Some nursing moms simply make lots of breast milk, which is known as an "oversupply." If you have oversupply, you may not technically need to supplement, but may still choose to if you want to breastfeed or pump a little less often or are gradually weaning.
Or you may want to breastfeed and pump (if you’re going back to work while nursing, or want a loved one to participate in the feeding, say), in which case you can refrigerate or even freeze the extra to give your little one later (breast milk lasts up to four days in the fridge and up to about 12 months in the freezer).
Instead, space out formula sessions, slowly adding in one or two more while pumping and freezing your excess.
Supplementing with formula with a low supply
If you find your supply is dropping as you supplement or you can’t establish enough milk to satisfy your infant, pumping each time you offer a bottle is the best way to keep your milk production flowing (and possibly increase the amount you can make).
It’s important to keep up the nursing and/or expressing of milk during your entire breastfeeding session (with a double pump, or after baby has drained one side), since missed or skipped sessions at the breast or pump tells the body to make less milk.
Supplementing with formula when going back to work
Heading back to the office and want to keep offering breast milk? Supplementing with formula lets you share feeding duties with a caregiver and can cut back a bit on the stress of being away from your baby while you’re still breastfeeding.
But to keep up your supply — and to continue nursing before and after work (if you’d like) — you’ll need to pump every time your baby has a bottle.
If you opt to pump less, know that the process doesn’t always correspond one-to-one. Which means that you might have enough milk to nurse when you’re not at work, but your supply could also drop more than the volume of the missed sessions.
Your best bet: Breastfeed when you’re with your baby, as contact with your infant is what keeps the milk-making hormones fired up.
Supplementing with formula at night
Offering formula at night is a little tricky because prolactin, the hormone responsible for making milk, peaks in the wee hours (between 2 a.m. and 5 a.m.).
Supplementing with formula during overnight feedings can actually impact your milk supply, but you can combat that potential issue by pumping when the baby is drinking a bottle.
Still, if you’re looking to night wean your little one off those sleepy, late nursing sessions, adding formula may be the way to go if you decide you’d like to give combo feeding a try.
Rest assured that though breast milk has plenty of benefits and it may be a tough decision to go the combo feeding route, you’re still giving our baby the nourishment she needs to thrive, and it’s always best to feed your baby in whatever way works for your family and situation (which can change fast). The formula of today is designed to mimic the natural stuff as closely as possible, so it’s packed with loads of vitamins and other nutrients.
Regardless of how you feed your baby, and for how long, keep up the good work! And know that with some careful planning, you can maintain your breast milk supply and still offer formula too.
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