Combination feeding — giving a baby both breast milk and formula — is far more common than many parents realise, yet it receives comparatively little guidance. The dominant narrative around infant feeding tends to be either fully breastfed or fully formula-fed, leaving many parents who are doing both without a roadmap.
There are many reasons a family might choose or need to combine feeding: insufficient milk supply, a baby who is not gaining weight on breastfeeding alone, a parent returning to work, medication that makes exclusive breastfeeding inadvisable, or simply a desire for more flexibility. Whatever the reason, combination feeding is a completely valid approach, and with the right information it can be structured to work well for both you and your baby.
The most important thing to understand about combination feeding is that breast milk supply works on a supply-and-demand basis. The more frequently and thoroughly the breast is drained, the more milk is produced. Every formula feed given in place of a breastfeed sends a signal to your body that the milk produced in that session was not needed, and over time supply adjusts downward accordingly.
This is not a problem to be avoided — it is simply how the system works, and knowing it allows you to manage it intentionally. You can choose to maintain full supply while supplementing with formula (possible but requires significant effort), to gradually reduce supply while increasing formula, or to find a stable middle point where you breastfeed some feeds and formula-feed others.
There is no single correct schedule for combination feeding. The right pattern depends on your supply, your baby's needs, and your own priorities. Here are some common approaches:
Breast first at every feed, formula top-up afterwards: This is often the approach recommended when combination feeding begins because of slow weight gain. The baby takes whatever is available at the breast, then receives a formula top-up to ensure they are getting enough. This approach maintains breastfeeding stimulation at every feed, which helps preserve supply. However, it can make feeds long and logistically complicated.
Designated breast feeds and designated formula feeds: Some parents choose to breastfeed at certain times of day — often the first morning feed, evening feeds, and any night feeds — and give formula at other times. This gives more predictability and allows the non-breastfeeding parent or a carer to give formula feeds. Supply tends to regulate around the feeds you consistently give.
Formula during the day, breastfeeding morning and evening: This pattern is particularly common among parents who return to work. It maintains the emotionally important early morning and bedtime feeds while making daytime care more flexible. Night feeds can be added depending on the baby's age and the parent's preference.
If your goal is to maintain breastfeeding at the feeds you have designated, consistency is key. Try to breastfeed at the same times each day as far as possible, so your body produces milk on a predictable schedule.
If you are replacing a breastfeed with a formula feed during a work day, pumping at that time can preserve your supply for that feed slot. This is particularly important in the early months when supply is still being established. After about 12 weeks, most breastfeeding parents find their supply is more robust and can accommodate some skipped pumping sessions without dramatically affecting output.
Stay hydrated and eat enough. This sounds obvious, but it is easily neglected in the chaos of early parenthood. Caloric restriction and dehydration both reduce milk supply.
Some babies accept a bottle of formula without any issue. Others resist it, particularly if they have been exclusively breastfed and are not used to a bottle at all. A few practical suggestions:
If your baby is strongly resistant, persist gently over several days before concluding that bottle feeding is not going to work. Most babies do eventually accept bottles when they are hungry enough and when the introduction has been made calmly.
If combination feeding began because of a temporary supply issue or poor early weight gain, many parents wonder when (or whether) they can return to exclusive breastfeeding. This is possible in some cases, particularly if the reason for the top-up has been addressed — for example, if a tongue tie has been treated, if latch has improved significantly, or if an early supply dip was related to poor establishment rather than a long-term issue.
The signs that it may be worth trying to reduce top-ups include: baby consistently gaining weight well, breastfeeds feeling fuller and more satisfying to the baby, the top-up being small (under 60ml), and supply feeling more established. Reduce top-ups gradually — by about 10 to 20ml every three to four days — and monitor weight to ensure adequate intake.
Working with a lactation consultant or infant feeding adviser during this process is genuinely helpful. In the UK, lactation consultants (IBCLC) are available privately, and many NHS trusts also offer specialist infant feeding support. La Leche League and the Breastfeeding Network also provide peer support from trained volunteers.
There is no right answer about whether to increase or decrease the formula component of a mixed feeding relationship. What matters is that your baby is thriving and that the feeding relationship works for your whole family.
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