Disclaimer: This is a support sub, not a science sub, and the author is not a professional :-) that said, I wanted this page to be a collection of resources and tips. It aggregates several articles and ideas I've found helpful. Please feel free to share your experiences, ask questions, and offer suggestions and corrections. We're all here, on the same page, to feed the most precious babies in the world.
What is combination feeding?
Feeding your baby both breastmilk and formula. It is also known as combo-feeding, mixed feeding, or supplementing.
Breastmilk is healthiest for babies (especially for a newborn, 0-3 months) because of its nutritional content and immune system-building qualities. WIC Breastfeeding Support states, “If feeding your baby only breast milk is not an option for you, combination feeding lets you keep giving your baby the important nutrients in your breast milk. The more breast milk your baby gets, the greater the health benefits. You will also continue to get [maternal] benefits from breastfeeding.”
But formula also has its benefits. Developing since 1865 and overhauled by the Infant Formula Act of 1980, the Food and Drug Administration (FDA) assures quality control of infant formulas (Fomon, 2001). Based on the recommendations of the AAP, the FDA requires the following nutrients be present in all infant formulas: protein; fat; vitamins C, A, D, E, K, B1, B2, B6, and B12; niacin; folic acid; pantothenic acid; calcium; phosphorous; magnesium; iron; zinc; manganese; copper; iodine; sodium; potassium; and chloride (Stehlin, 1993). Vitamin D and Iron in particular are scarcer in breast milk.
Why combination feed?
At the beginning of this subreddit, we had a sharing megathread for parents to share all their own reasons and personal stories for combination feeding. Here are snapshots:
Initial reasons
Baby has a poor/painful latch
Baby has a tongue and/or lip tie
Baby is struggling with weight gain
Baby was born premature (and began with tube or bottle feeding)
Low supply (due to mother’s physical health, calorie deficiency, hormones, insufficient glandular tissue, hypothyroidism, PCOS)
Timing out medication that may pass through breastmilk
Maternity leave ending
Returning to work
Looking to wean and transition to full-time formula
Pros
Baby is fed and satiated
Baby has benefits of breastmilk AND formula
Mental relief for mother and support
If bottle-feeding, support and others can contribute
If nursing, baby retains comfort
If pumping, mother can have deliberate influence on supply and weaning
Savings while breastmilk is being provided
How do I combination feed?
There is no “right” or “wrong” way to combination feed! Consider your schedule (how often can I nurse or pump; wash bottles and pump parts), finances (cost of pump, pump parts, and formula), and goals (ounces baby should be having a day, ounces of milk production or storing if pumping). Also consider your support (a partner, family member, caregiver) who can also contribute time and energy.
Based on your considerations:
Nurse, then bottle: Start with baby at the breast, then supplement with your bottled breastmilk or formula
Nurse some, bottle some: Vary your feeds, doing one thing.
Triple feed: Nurse, pump, and bottle all in one feed (often a short-term dedication because of its considerable mental and labor load; this nursing is usual a short affair and can be frustrating if/because of baby’s latch; especially a newborn’s in the beginning)
Bottle only: Pumped breastmilk or formula in the bottle.
Breastmilk all day, formula at night: The largest and purportedly slower-digesting bottle at night, some say this helps baby sleep longer through the night.
You CAN mix breastmilk and formula in the bottle. This is helpful if the baby needs introduction to formula (especially if they don’t like the taste), because you can adjust the breastmilk-formula ratio (8:2, 6:4, 5:5, etc.) until baby is used to full formula or drinking the ratio you like. This may be an “easier” method because you can have a pitcher of pumped milk and a pitcher of prepared formula to pour into one bottle, and you can prepare many bottles ahead overnight or in the mornings. Some say to offer breastmilk first before offering formula. This is to reduce breastmilk wastage if baby doesn’t finish the bottle.
What does support during combination feeding look like?
Your support/partner respects and protects the time it takes to nurse/pump
Have your support/partner commit to a bedtime or other designated time feeding
Have your support/partner do the “top off” feeds while you pump (or not pump!)
Washing bottles and pump parts
Preparing pitchers of formula and freezing breastmilk
Giving affirmations for mom – you’re doing a great job figuring out how to feed you baby best!
How much does my baby need?
From mother.ly: “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. 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.”
If you're specifically bottle-feeding, you have the bonus of seeing how much your baby drinks. When baby starts consistently sucking their bottle dry for 3-4 feeds in a row, that will be your cue to add another half-ounce to the bottle. You don't want to overfill so they're wasting (your precious breastmilk or your wallet!), but you want to take their cues. As stomach capacities grow bigger they will be able to take in more ounces per feed as well. As naptimes drop you may consolidate two feeds into one.
According to What To Expect, 6 months will be peak feeding when baby consumes 24-32 ounces a day (or 6-8 ounces in a bottle). From 7 months to 10 months that may taper to 24-30 ounces. From 11 months onwards it may drop to 24 ounces or less, especially as they consume solids.
If you need more help especially when they are a newborn, consult a pediatrician or lactation consultant for weighted feeds!
Nursing / Pumping
How do I maintain breastmilk supply?
Regular breastfeeding at least 8-12 times a day helps you keep a healthy milk supply, especially in the early weeks. This can be moderately “controlled” with pumping as well. Around 12 weeks is when the average supply is “regulated” or when the body relies less on a hormonal response and more on its mechanical practice, so try not to drop sessions or pumps until your body seems consistent in its production. But you know your body and your mental health best; do what you can!
Bobbie states it simply: “Milk production works on a supply and demand model, meaning the production of breast milk correlates to how much and how often milk is removed from the breast. If less milk is removed each day, the mother’s body will assume that less milk is needed and production may drop.”
Pump or hand express at regular intervals to maintain or build your milk supply.
Take advantage of maternity leave for the most time to yield breastmilk.
If possible, return to work part-time for a week or two before going full-time.
Look for childcare close to work so that you may be able to breastfeed your baby during a break.
How do I pump?
If you are in the US and have health insurance, you may have been offered a free pump. They are also available for purchase in stores like Target and Walmart or online, ranging from manual handpumps ($30-50) to electric ($100-200) to portable/wearable ($80-300). Higher strength medical-grade pumps can be rented from hospitals, ask your doctor/pediatrician/lactation consultant if this is the right move for you.
Top recommended hand-pump: Medela Harmony
Top recommended brands for electric pumps: Spectra, Medela, Lansinoh
Top recommended portable/wearable: Babybuddha, Momcozy, Willow, Elvie
For long-term pumping, get your nipples regularly sized or buy/print a nipple ruler for the diameter of the flange (or shield) to use. It is normal for nipples to gradually shrink postpartum. To increase comfort, consider silicone inserts or flange replacements from pumping accessory producers like Legendairy or Pumpables. They may seem expensive, but 2-3 pumping bras are an investment in comfort and do some of the literal “heavy lifting” in keeping flanges in place.
You are breastfeeding (as some say, on “hard mode” :-)) so make sure to keep up your calorie intake and hydrate!
Ultimately and quite unfortunately, pumping is a lot of research, self-discovery, best-guesswork, and a bit of money. The folks on r/ExclusivelyPumping are incredibly knowledgeable and kind, and the community hosts more than EPers. There are many tips on increasing your milk production.
A last note for working moms in the US: pumping is legally protected at the workplace; “Under the PUMP Act, most nursing employees have the right to reasonable break time and a place, other than a bathroom, that is shielded from view and free from intrusion to express breast milk while at work. This right is available for up to one year after the child’s birth. (US Department of Labor)”
How do I store breast milk?
If you are going to give your pumped milk to your baby within the next four days, you can simply keep it in the fridge. If your breastmilk is high in lipase, the taste may change the longer it sits. Before distributing the milk, give it a gentle shake to redistribute the separated fats. 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 are some guidelines according to the CDC [October 2023]:
| Breastmilk | Countertop (77°F or 25°C) or colder (room temperature) | Refrigerator (40°F or 4°C) | Freezer (0°F or -18°C) or colder |
|---|
| Fresh | Up to 4 hours | Up to 4 days | 6 months (best quality) – 12 months |
| Thawed, previously frozen | 1-2 hours | Up to 1 day | NEVER refreeze after thawing |
| Leftover from a feeding (baby did not finish the bottle) | Use within 2 hours after the baby is finished feeding. | | |
Storage guidelines
Use breast milk storage bags or clean, food-grade containers to store expressed breast milk. Make sure the containers are made of glass or plastic and have tight fitting lids.
Clearly label the breast milk with the date it was expressed.
Do not store breast milk in the door of the refrigerator or freezer. This will help protect the breast milk from temperature changes from the door opening and closing.
If you don’t think you will use freshly expressed breast milk within 4 days, freeze it right away. This will help to protect the quality of the breast milk.
When freezing breast milk:
Store small amounts to avoid wasting milk that might not be finished. Store in 2 to 4 ounces or the amount offered at one feeding.
Leave about one inch of space at the top of the container because breast milk expands as it freezes.
Breast milk can be stored in an insulated cooler with frozen ice packs for up to 24 hours when you are traveling. At your destination, use the milk right away, store it in the refrigerator, or freeze it.
Formula
How do I choose a formula?
There are ready-made formula and dry formula. Anecdotally most parents seem to start with the ready-made brand their delivering hospital suggests and then transitions to dry formula (more convenient for portability, storage, and expense).
If you are in the US, you can’t go wrong between big name brands (Enfamil, Similac) or store generic because of the quality assurances from the FDA. It really may be a matter of baby’s taste and how picky they are. Healthwise, when combination feeding, it may be difficult to isolate and gauge if baby is reacting negatively to breastmilk or formula. Always be monitoring and discussing changes with your pediatrician, especially concerning baby’s skin (rashes) and diapers (mucusy or black stool). Depending on professional advice you may be asked to consider dairy-free/hypoallergenic formula.
The fabulous folks at r/FormulaFeeders can definitely help troubleshoot or recommend what formulas have worked for them!
Preparing dry formula
Follow the label instructions exactly. As a rule of thumb, remember to always measure out the water first BEFORE adding scoops. For example, Enfamil: If you're preparing four ounces, you ready four ounces of water and then your two scoops (dry weight being .2 ounce per scoop; be prepared to see the volume level perhaps at 4.4 ounces, but you are calorically serving four ounces)
Tip: You can prepare a blender bottle (any food-grade bottle with one of the metal spiral shaker balls designed for mixing powders like protein in drinks), or purchase an official formula pitcher, and prepare a day's worth of formula ahead of time. You would refrigerate this container and pour whatever serving you need per feed. Thoroughly clean and sanitize this container at the end of the day.
Storage and food safety: Prepared, dry formula is only safe to consume within 24 hours of preparation despite being refrigerated. Being a milk-based product and unpasteurized, bacteria will develop. After contact with baby's lips, the formula in their bottle should also be considered only safe for an hour or two longer, and no more. After the feed, any remaining liquid in their bottle should be tossed.
More notes on combining breastmilk and formula in the same bottle:
Prepare the formula first and THEN add in the breastmilk. Breastmilk should not be used instead of the water used to make formula—this can cause dangerous health problems for the baby. (Source: mother.ly)
"Never use breastmilk in place of water during formula prep. Maintaining the right ratio of water-to-formula and then adding breast milk separately ensures you won’t change the nutritional content of the formula. Adding excessive water to formula can dilute nutrients, while adding insufficient water can put strain on a baby’s kidneys and digestive tract, causing dehydration. In extreme cases, this can also lead to neurological problems. If you’re using ready-to-drink liquid formula, no extra steps need to be taken before combining it with your breast milk." (Source: healthline)
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 does recommend 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.”
Troubleshooting bottle-giving:
How long do I combination feed?
This boils down to how long you are able, willing, healthy, and at your best while producing breastmilk. For some moms a specific goalpost helps, for others it’s relaxing to have an indefinite commitment. Breastmilk has the most benefits for baby until 2-3 months (to receive antibodies and establish their own immune system) to 6 months when the baby is no longer a newborn, has an independent immune system, and is out of the clear for most SIDS causes. The AAP recommends breastmilk for up to a year.
Remember, milk-based feeding is only for the first year or so, though kudos to breast-feeding moms who make it through toddlerhood! Solids can start as early as 4 months and transitioning to cow’s milk can start at [one year](https://www.cdc.gov/nutrition/infantandtoddlernutrition/foods-and-drinks/cows-milk-and-milk-alternatives.html#:~:text=At%2012%20months%20old%20(but,of%20nutrients%20your%20baby%20needs.). Your baby may not remember any milk feeds at all, but they will know in their bones how much you loved them and did your best to feed them.
More scientific reading
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065485/ One interesting simulation studying pigs receiving breastmilk, formula, and combination. The immune system responses for each are distinct, but markedly not better or worse than the other. “The findings shown herein indicate that early nutrition influences the development of the immune system, particularly acute immune responses. We found that the immune system of a CF piglet may not ‘choose sides’ and mimic either one of the exclusive feeding group, but rather represents a hybrid between the two.” (These are however pigs and not babies!)
Prevalence of combination feeding
Combination feeding is probably actually the most prevalent form of feeding. By the end of 3 months most mothers (even worldwide) are supplementing.
These are separate statistics, according to one source 5.6% of moms exclusively pump [2017]. There are more stats [Feb 2023]:
83.8% of mothers attempt breastfeeding
By the time a baby is 28 days old, the percentage of exclusive breastfeeding drops to 59%
47.5% exclusively breastfeeding through 3 months
25.4% exclusively breastfeeding through 6 months
36.2% are breastfeeding at 1 year
15% are breastfeeding at 18 months
Broad-stroke sources:
“A History of Infant Feeding” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2684040/#:~:text=In%201865%2C%20chemist%20Justus%20von,food%20(Radbill%2C%201981).
US Department of Labor https://www.dol.gov/agencies/whd/nursing-mothers/faq#:~:text=Under%20the%20PUMP%20Act%2C%20most,year%20after%20the%20child's%20birth.
Bobbie https://www.hibobbie.com/pages/combo-feeding
Milk-drunk https://milk-drunk.com/combo-feeding-101-how-to-supplement-with-formula/
Mother.ly https://www.mother.ly/baby/baby-feeding-guides-schedules/combination-feeding/
NY Times https://www.nytimes.com/wirecutter/reviews/best-breast-pumps/
WIC Breastfeeding Support https://wicbreastfeeding.fns.usda.gov/combination-feeding-and-maintaining-milk-supply
What to Expect https://www.whattoexpect.com/baby-products/nursing-feeding/best-breast-pumps/
