Many parents are nervous about supplementation. You may have heard that using supplements is the beginning of the end of your breastfeeding relationship, or that infant formula has risks associated with it. It is not true that supplementing has to hurt breastfeeding; in fact, ensuring your baby gets enough calories helps them breastfeed better. While all feeding has risks (cut those grapes in half for your toddler!), those of infant formula have been overblown to the point of absurdity.
What kind of milk to use
Use your pumped milk first. If your baby needs more, infant formula is modeled after human milk and provides the appropriate calories, fluids, and nutrition for babies. I suggest starting with a basic cow’s milk based formula, ideally generic (half as expensive and contains the same nutrients). For parents who wish to use screened, pasteurized donor breastmilk, here is a resource.
How much to feed
Here are typical feeding amounts for babies by age. Depending on how much milk your baby is getting from breastfeeding, how much weight they need to gain, and how hungry/thirsty they are, they may take more or less. Always feed your baby until they show signs of being comfortably full.
Day One: 0.5 oz (10–15 ml)
Day Two: 0.5–1 oz (15–30 ml)
Day Three: 1–1.5 oz (30–45 ml)
Day Four: 1.5–2 oz (45–60 ml)
Day Five to Six Months: 2.5 oz/pound of body weight/day (see breast milk calculator)
Almost always, you can trust your baby to tell you when they are hungry and when they are full. The exception is if your newborn is too tired to eat, in which case, you may need to be a little pushy. You should make sure your baby eats at least eight times a day.
Watch for Hunger Cues
Start With Breastfeeding
Start with breastfeeding on both breasts before you supplement, so your body will get a strong signal to make milk. (Make sure you understand how to maintain or increase your supply if needed.) If your baby is too sleepy to wake up and latch, skip ahead to the next section and read about syringe feeding and bottle-feeding.
Make sure your baby is latched on correctly
Babies who are latched on correctly will get more milk and not hurt your nipples. Learn more here.
Maximize the flow of milk from your breast while baby is breastfeeding
Note: When the speaker says the word “there,” that indicates the baby swallowing a big mouthful of milk (watch baby’s chin).
Supplementing at the Breast
Curved tip syringe at the breast
Here's how to use a curved tip syringe (available at hospitals, pharmacies, and Amazon) to give breastmilk or formula, while baby nurses. Your hospital may have different types of feeding syringes that will work also. First, your baby must be latched on. Slightly pull back their cheek a tiny bit, just enough so you can see the corner of their mouth. Insert the syringe about 1/3 to 1/2 of the way with the point towards their cheek.
Make sure baby is still latched, then very gently push the plunger to release milk. It’s important that you can feel the baby pulling; if they’re not sucking, this will not work well. Slurping noises indicate baby is not fully latched; take baby off and relatch them, then insert the syringe again.
Sometimes babies will suck the milk out of the syringe themselves, in which case, let them—less work for you! Notice how the baby's sucking pattern changes once the syringe is in her mouth—this is exactly what you will see when your milk comes in and your baby is swallowing gulps of milk. Tongue and lip ties are referred to in the video; learn more here.
Supplemental Nursing System
Like with a curved tip syringe, a supplemental nursing system allows you to slip a thin tube into the corner of your baby’s mouth, so they can get supplemental milk while nursing. This has the advantage of providing breast stimulation (if the baby has an effective latch and is pulling on mom’s nipple, not using the tube as a straw), while also getting their full feeding at the breast. This can be helpful when a baby is frustrated with a slow-flowing breast (slow flow often comes with low supply).
Syringe and finger
The advantage of this method is that it allows you to collect and feed tiny amounts of colostrum. It should be noted that there is no advantage to using a finger over a bottle nipple; a bottle nipple is softer and more like a human nipple than a bony finger (see video below).
Small amounts of colostrum can also be put directly into a bottle nipple (without the bottle attached). This is easier and reduces the risk of spillage.
Bottle-Feeding
Recommended Bottle Nipples
Good latch onto bottle nipple
Bottle feeding a baby does not have to be complicated. Here are some tips, but even if you just wing it, most babies do fine going back and forth between breast and bottle.
Use a slow-flow newborn sized nipple. Hold your baby in a comfortable, slightly upright position, with the bottle horizontal. Tip it slightly so milk is filling the nipple. Tickle baby’s lips with the nipple and wait for them to open their mouth wide—just like you would with the breast—before putting the nipple in. If your baby is too sleepy to eat and they need to, you can wiggle the nipple into their mouth. Stroke the roof of your baby’s mouth until they start sucking.
Do not waterboard your baby—let them control the flow, without gravity doing the work.
If your baby is eating too fast and appears uncomfortable (milk leaking around the lips, stressed facial expression, coughing or turning away from the bottle), give baby a break, and check that the nipple isn’t flowing too fast. If your baby appears frustrated, or the nipple collapses during sucking, the nipple may be too slow.
Micromanaging the feeding is not necessary; your baby will not overeat when they can control the flow and you’re using upright positioning and watching their fullness cues. (Note that occasional spit-up happens and does not mean you overfed your baby; their stomachs are just immature at this point in time.)
Once your baby’s saliva has touched the nipple, any milk left in the bottle after the feeding must be thrown out: within two hours for breastmilk, and one hour for formula. Here are the CDC guidelines for preparation and storage for breastmilk and formula.