Mixing breastfeeds with bottles of expressed milk or formula can work well, but bottles change the signals your body uses to make milk. Here is when the NHS suggests starting, which feed to swap first, how fast to go, and how to keep your supply steady.
Last reviewed 12 October 2026 · Checked against NHS guidance · 13 min read
The short answer
Combination feeding (also called mixed feeding) means breastfeeding alongside bottles of expressed breast milk, infant formula, or both. The NHS recommends breastfeeding exclusively for the first 6 to 8 weeks if you can, so your supply settles. Then replace one breastfeed a day with a bottle and allow your breasts around 5 to 7 days to adjust before changing another. To protect your supply, keep breastfeeding regularly, put breastfeeds first where possible and express between bottle feeds. Use a slow-flow teat and paced bottle feeding.
This guide sits between two of our main guides: what to eat while breastfeeding, for your own meals and drinks while you make milk, and when to start weaning in the UK, for when food joins milk at around 6 months. Here we answer one question: how to add bottles without your milk supply quietly dropping away. Every point comes from current NHS guidance.
What combination feeding means, and why parents choose it
The NHS describes several ways of mixed feeding: breastfeeding plus bottles of expressed milk, formula, or both, or bottle feeding only with expressed milk, with or without formula. There is no single right mix. What matters is changing it slowly.
The NHS lists these common reasons for combining breast and bottle:
It is also a gentle way to wind down: the NHS says topping up with formula lets you reduce or stop breastfeeding gradually.
When to start: the 6 to 8 week rule
Whatever your reason, the NHS recommends breastfeeding exclusively for 6 to 8 weeks after the birth if possible. That gives you time to get the hang of breastfeeding, and exclusive breastfeeding helps stimulate your milk production. The NHS also says mixed feeding is usually possible once you and your baby are comfortable with breastfeeding, which can take several weeks.
The reason is timing. Bottle feeds mean longer gaps between breastfeeds, which tell your body less milk is needed, and the NHS says this matters most in the first 6 to 8 weeks. Its milk supply guidance says the same about formula top-ups: wait until breastfeeding is well established.
Advised to top up earlier, or finding breastfeeding hard?
The 6 to 8 week guide is the ideal, not a test you have failed. If you are worried your baby is not getting enough milk, the NHS says to speak to your midwife or health visitor, who can check feeding with you and help plan any top-ups.
Why bottles can lower your milk supply
Breast milk is made on a supply and demand system. Generally, the more your baby feeds, the more milk you produce. Long gaps between feeds may reduce how much you make. So every bottle that replaces a breastfeed, rather than adding to it, sends a "make less" signal.
The NHS explains three ways bottles do this:
- Fewer feeds at the breast. Topping up with formula means your baby breastfeeds less often, which tells your breasts to produce less milk.
- A fuller baby. Filling your baby up with first infant formula can reduce their wish to feed. Fewer feeds means less milk.
- Longer gaps. When a bottle covers a feed, the time between breastfeeds stretches, and your body reads that as needing less.
Introducing formula will probably reduce the milk you make, the NHS says, but going gradually gives your body and your baby time to adjust, and stops your breasts becoming sore, too full or leaking.
Which feed to swap first?
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A gentle starting point, not a personal plan. The Combination Feeding Education course helps you plan your feeds week by week.
Swapping your first feed, step by step
The NHS starting point is simple: replace one breastfeed a day with a bottle. Generally, each breastfeed you drop is replaced with one bottle. After you swap a breastfeed for a formula feed, your breasts may take around 5 to 7 days to adjust. Only then think about the next swap.
- Pick a calm momentOffer the first bottles when your baby is calm, not tired or very hungry. Babies are less likely to accept something new when they are tired or hungry.
- Let someone else trySomeone else may find it easier to give the bottle, so your baby is not smelling your milk.
- Use a slow-flow teatThe NHS suggests a slow-flow teat to mimic the flow of breastfeeding.
- Copy your breastfeeding positionsWhen bottle feeding, try the positions you would use when breastfeeding, or try different positions for each.
- Keep breastfeeding regularlyPrioritise breastfeeding where possible, and express between bottle feeds to help maintain your supply.
- Go at your baby's paceIt may take a while for your baby to get used to a new way of feeding. Take your time.
One safety point applies to every feed, breast or bottle: do not feed your baby while they are in a sling or carrier. Take them out first so they are in a safe feeding position.
Can a bottle at bedtime help my baby sleep longer?
Some parents swap the bedtime breastfeed for a bottle, hoping for better sleep. The NHS says very young babies need to feed little and often, so this is probably not effective for a newborn, and a big feed does not mean a longer gap before the next.
Expressed milk or formula in the bottle?
Both work. The difference for supply is what happens at your end while the bottle is given.
Expressed breast milk
- Expressing keeps your breasts producing milk, so you can restart breastfeeding easily after a break.
- Express by hand or with a manual or electric pump. Allow 30 to 45 minutes at first; with practice, both breasts may take about 15 to 20 minutes. Wash your hands first and sterilise a pump before use.
- Stored milk keeps up to 8 days in a fridge at 4°C or lower. See our breast milk storage guide for freezer and room times.
Infant formula
- First infant formula is the only formula your baby needs in their first year, unless a health professional advises otherwise. Follow-on formula should never be given under 6 months.
- Always follow the manufacturer's instructions when making up formula. Our step-by-step guide shows how to make up a formula feed safely.
- When your baby is full, throw away any leftover milk. Unused formula at room temperature must be thrown away within 2 hours.
On amounts, the NHS says responsive ("on demand") feeding helps prevent overfeeding, and your baby will show you how much they need. Our guide to how much formula by age covers the NHS amounts.
Formula top-ups: temporary or long term?
The NHS uses "top-up feeds" to mean giving some formula alongside your breast milk. Before you start, decide which of these you are aiming for, because the supply advice is different:
- A temporary top-up, and you want to keep breastfeeding. Expressing your breast milk will help maintain your supply while your baby has formula.
- You want to reduce or stop breastfeeding. Topping up with formula lets you do this gradually, one feed at a time.
- You are worried your baby is not getting enough. Speak to your midwife or health visitor first.
Signs breastfeeding is going well
Before reaching for formula because of supply worries, check what the NHS says a well-fed breastfed baby looks like:
- Long, rhythmic sucks and swallows with pauses, and your baby seems content after most feeds.
- From day 5, at least 6 wet nappies every 24 hours, and at least 2 soft yellow poos a day by about days 5 to 6.
- Steady weight gain after the first 2 weeks. Some early weight loss is normal.
If these signs are missing, talk to your midwife or health visitor before adding formula.
Paced bottle feeding: keep bottles closer to breastfeeding
The NHS describes paced feeding as a way of bottle feeding that gives your baby more control and mimics breastfeeding. Your baby draws the teat in and sets the pace, and has time to feel full.
- 1Hold close, semi-uprightSupport their head so they can breathe and swallow comfortably.
- 2Invite, don't pushRub the teat on their top lip. When they open wide, let them draw it in.
- 3Bottle almost horizontalTip it only slightly, so milk does not flow too fast.
- 4Pause when they askSplayed fingers, turning away or stopping sucking? Lower the bottle for a break.
- 5Stop when they've had enoughNever make them finish. Hold upright and gently rub or pat their back.
A few more NHS points:
- If the teat goes flat, gently pull the corner of your baby's mouth to release the seal.
- If your baby gets upset when you take the teat out for a break, tilt the bottle down with the teat still in their mouth to slow the flow instead.
- Feed at early hunger cues such as sucking on hands or fingers, rooting, wriggling, or opening and closing the mouth. Crying is the last sign of wanting to feed.
- Never prop a bottle and leave your baby alone to feed, as they may choke.
The NHS also suggests parents or main caregivers give most feeds, especially in the early weeks, to help with bonding.
Want to practise it? Combination Feeding Education walks you through paced bottle feeding alongside planning your feeds and protecting your supply.
If your breastfed baby refuses the bottle
The NHS says bottle refusal is especially common in babies who have breastfed successfully for some time. Your baby may need time to get used to the feel of the teat. Go slowly, use the first-bottle steps above, and offer bottles when your baby is calm and happy. From 6 months, a baby who can drink from a cup may not need a bottle at all.
What about bottles putting your baby off the breast? The NHS does not use the term "nipple confusion". Its latching advice is about dummies, which are sucked differently and may interfere with learning to latch, so it suggests avoiding them until breastfeeding is established, usually after about 1 month. A slow-flow teat and paced feeding keep bottles close to breastfeeding.
Protecting your supply: a quick checklist
Seven habits that keep your milk flowing while bottles join in. Every item comes from NHS mixed feeding and milk supply guidance.
- One swap at a time. Replace one breastfeed a day, then allow around 5 to 7 days before the next.
- Breastfeeds come first. Prioritise breastfeeding where possible and keep feeding regularly.
- Express when a bottle replaces a feed. Regular expressing between bottle feeds helps maintain your supply.
- Both breasts, switching sides. Offer both breasts at each feed, switching sides each time.
- Skin to skin. Hold your baby close, especially skin to skin.
- No dummy yet. Avoid a dummy until breastfeeding is established, usually after about 1 month.
- Solids can wait. Hold off on solid food until around 6 months.
If you want to cut down further, the NHS says to allow about one week for each feed you drop, and to slow down if, for example, your baby is unwell and wants to breastfeed more. If it is proving difficult, take a break and try again in a few weeks.
For babies under 1, replace dropped breastfeeds with first infant formula. Babies under 6 months must be bottle fed, and babies older than 6 months can have the feed from a beaker or cup. If you are planning your return to a job, the NHS suggests starting formula feeds a few weeks beforehand. Our guide to breastfeeding when you go back to work covers planning feeds around your job in more detail.
Sore, full breasts and mastitis
Dropping feeds too quickly can leave milk building up in the breast faster than it is removed. The NHS calls this milk stasis: it can block milk ducts and lead to mastitis. That is the main reason it advises cutting down gradually.
Speak to your GP, midwife or health visitor if...
your breast feels swollen, hot and painful to touch, or you have red patches (harder to see on brown and black skin). The NHS says inflammation can sometimes develop into an infection, and you may feel achy and run down, with flu-like symptoms or a fever. Get advice promptly rather than waiting, and slow down any feed changes in the meantime.
Vitamin D for mixed-fed babies: the 500ml rule
This is where combination feeding catches parents out. Infant formula is fortified with vitamin D, breast milk is not, so the NHS bases its advice on how much formula your baby drinks:
| Your baby (birth to 1 year) | Daily vitamin D drops? | What the NHS says |
|---|---|---|
| Breastfed, or mixed fed with less than 500ml of formula a day | Yes | A daily supplement containing 8.5 to 10 micrograms of vitamin D, from birth, whether or not you take vitamin D yourself. |
| Having more than 500ml (about a pint) of infant formula a day | No | No vitamin supplements, because formula is already fortified with vitamin D and other nutrients. |
Check where your baby sits each time you swap a feed. From 6 months up to 5 years, the NHS recommends daily vitamin A, C and D drops, again unless your baby is having 500ml or more of first infant formula a day. Read the label to check drops are age appropriate. If you are under 18 or on benefits, you may be entitled to free Healthy Start vitamin drops, and in some areas they are free to all families: ask your health visitor.
Going back to breastfeeding more
If you have been giving bottles and want to breastfeed more, the NHS is honest that it can take time, because low supply is hard to increase. Its suggestions:
- Hold your baby skin to skin as much as possible, including during feeds. This encourages your body to make milk and your baby to feed.
- Breastfeed as often as possible while your baby is calm and relaxed. Feed often when your baby is latching on, and do not force feeds.
- Start each feed with the breast your baby did not feed from last, or only fed from a little.
- Express regularly, about 8 times a day, including once at night.
- Try bottle feeding skin to skin, close to your body.
- Reduce bottles gradually as your supply increases, and avoid solid foods until around 6 months.
A lactation aid (supplementer) is another option: your midwife, health visitor or breastfeeding supporter can advise. If you are still worried, ask your midwife to refer you to a breastfeeding specialist, who can watch your baby feed and give practical help.
Where to get help with mixed feeding
For one-to-one support, talk to your midwife, health visitor or a trained local breastfeeding supporter. The NHS also lists these helplines:
Make a plan you can actually follow
Our courses turn these rules into a plan for your own baby and your own week.
Combination Feeding Education
Plan your feeds, protect your milk supply and get confident with paced bottle feeding, so breast and bottle work together.
Formula Feeding Basics
Making up feeds, sterilising, amounts by age and a simple feeding log, for the formula side of mixed feeding.
Related guides
- Breastfeeding and going back to work: planning feeds around your job.
- Breast milk storage times (UK): fridge, freezer and room temperature.
- How much formula by age: NHS amounts and feeding cues.
- What to eat while breastfeeding: your own food, drinks and vitamin D.
Questions parents ask
When can I start combination feeding?
The NHS recommends breastfeeding exclusively for 6 to 8 weeks after the birth if possible, so you get the hang of it and your milk supply settles. Mixed feeding is usually possible once you and your baby are comfortable with breastfeeding. If you are struggling or have been advised to top up sooner, talk to your midwife or health visitor.
Will combination feeding reduce my milk supply?
It can. Bottle feeds make the gaps between breastfeeds longer, which tells your body less milk is needed. To protect your supply, keep breastfeeding regularly, prioritise breastfeeds where possible, express between bottle feeds and swap only one feed at a time.
How do I introduce formula to a breastfed baby?
The NHS suggests replacing one breastfeed a day with a bottle. Your breasts may take around 5 to 7 days to adjust before you swap another. Offer the bottle when your baby is calm rather than tired or very hungry, use a slow-flow teat and always follow the formula manufacturer's instructions.
Does a combination-fed baby need vitamin D drops?
If your baby has less than 500ml of infant formula a day, the NHS advises a daily vitamin D supplement of 8.5 to 10 micrograms from birth, as for breastfed babies. Babies having more than 500ml (about a pint) of formula a day should not have vitamin supplements, because formula is already fortified.
What if my breastfed baby won't take a bottle?
The NHS says this is common, especially if your baby has breastfed for some time. Go slowly, offer the bottle when your baby is calm and happy, and let someone else try so your baby is not smelling your milk. From 6 months, a baby who can drink from a cup may not need a bottle.
Can I give formula at night and breastfeed in the day?
You can choose which feeds to swap, but the NHS notes that very young babies need to feed little and often, so a bedtime bottle is probably not effective for a newborn. A big feed does not mean a longer gap, and babies usually need night feeds for at least the first few months. Change one feed at a time.
Can I go back to exclusive breastfeeding after giving formula?
Often, yes, but it can take time because low supply is hard to increase. The NHS suggests skin-to-skin contact, breastfeeding as often as possible, expressing about 8 times a day including once at night, and reducing bottles gradually. Your midwife can refer you to a breastfeeding specialist.
Sources
- NHS Best Start in Life: Introduction to mixed feeding
- NHS Best Start in Life: Introducing formula feeds
- NHS Best Start in Life: Adjusting your milk supply
- NHS Best Start in Life: Mixed feeding challenges
- NHS Best Start in Life: Top up feeds
- NHS Best Start in Life: How to express your breast milk
- NHS Best Start in Life: Help and support with mixed feeding
- NHS: Combining breast and bottle feeding
- NHS Best Start in Life: Milk supply
- NHS Best Start in Life: How to bottle feed
- NHS Best Start in Life: Feeding on demand
- NHS: Bottle feeding advice (last reviewed 2 April 2024)
- NHS: Types of infant formula
- NHS Best Start in Life: Baby vitamins
- NHS: Vitamins for children (last reviewed 30 May 2024)
- NHS: Vitamin D
This article is general information based on UK public health guidance. It is not medical advice. If your baby was born prematurely, is not gaining weight, has a health condition, or you have questions about your own feeding, speak to your midwife, health visitor or GP.
