Breastfeeding or formula? An honest guide
No guilt, no agenda — just what the evidence actually shows, what it doesn't, how to feed safely whichever way you choose, and how to know your baby is getting enough.
🌿 Open the Feeding Your Baby lesson in WiseMama — freeThe honest starting point
Few topics in early parenthood generate more conflicting advice — or more unnecessary guilt — than feeding. Breastfeeding is presented as the only serious choice, and formula feeding as a compromise. Neither framing is accurate or helpful.
WiseMama's position is straightforward. Breastfeeding has well-documented benefits that are worth presenting honestly. So does formula feeding — and these are practical, significant, and worth naming clearly rather than treating as a footnote.
Formula feeding is not a compromise or a failure. It is a safe, nutritionally complete way to feed a baby, and it offers practical advantages that matter enormously to many families:
- Some people cannot breastfeed — due to previous surgery, medication, certain medical conditions, or milk supply that cannot be established despite support
- Illness, severe exhaustion, or postnatal mental health difficulties can make breastfeeding unsustainable, and formula provides a way to continue feeding while recovering
- Formula feeding allows feeding to be shared between partners and other caregivers — a significant factor for maternal recovery, sleep, and mental health
- Returning to work is a reality for many families, and formula provides flexibility that expressing does not always make possible
- For some people, the pressure and difficulty of breastfeeding causes more harm — physically and emotionally — than the benefits justify
How you feed your baby matters less than the fact that your baby is fed, that you are supported, and that you have accurate information. That is what this page is for.
What the evidence shows about breastfeeding
Breast milk is not just nutrition — it is a biologically active substance. It contains antibodies, living white blood cells, enzymes, hormones, and growth factors that formula cannot replicate. Formula milk does not provide the same protection from illness and does not give the mother any health benefits. This is not a marketing claim; it is physiology.
For the baby
The evidence is strongest for infectious illness in infancy. Breastfed babies have meaningfully lower rates of:
- Gastrointestinal infections — diarrhoea and vomiting, fewer hospital admissions
- Respiratory infections — including bronchiolitis and pneumonia
- Ear infections (otitis media)
- Necrotising enterocolitis (NEC) in premature infants — one of the strongest and most clinically significant effects
- SIDS risk — some evidence of a modest reduction
Evidence for longer-term outcomes — obesity, type 2 diabetes, IQ, educational attainment — exists but is considerably more complex. The associations between breastfeeding duration and cognitive scores persist after adjusting for socioeconomic factors and maternal cognitive ability, however the effect was modest. In a UK context where breastfeeding rates are strongly associated with socioeconomic status, unpicking what is caused by breastfeeding from what is caused by other advantaged conditions is genuinely difficult.
For the mother
The maternal benefits of breastfeeding are less well-publicised but substantial:
- Reduced breast cancer risk — the risk of breast cancer is reduced by 4.3% for every 12 months of breastfeeding.
- Reduced risk of ovarian cancer and type 2 diabetes
- Faster uterine involution after birth
- Delayed return of menstruation (though this is not a reliable contraceptive)
The honest caveats
The evidence is observational in most cases — randomised controlled trials of breastfeeding versus formula are not ethically feasible. This means it is difficult to fully exclude confounding: in the UK, low socioeconomic status was found to negatively impact breastfeeding, and women from more advantaged backgrounds are more likely to breastfeed and to breastfeed for longer. Many of the associations attributed to breastfeeding may partly reflect other advantages in the environments where breastfeeding is most common.
This doesn't mean the benefits aren't real — there are good biological mechanisms for them and some of the strongest evidence (on gut infection and NEC in premature infants) comes from contexts where confounding is less of a concern. But it does mean that the presentation of breastfeeding benefits in popular media — as though formula-fed children are substantially disadvantaged — overstates what the evidence shows at the individual level.
I breastfed my first for two weeks before switching to formula because it simply wasn't working and I was in pieces. My second I managed for six months. Both are thriving, identical in health, and I genuinely cannot tell which was which from their development. What mattered was that I got proper support — and got it quickly — rather than being told to try harder.
Formula feeding: what you need to know
Which formula to buy
First infant formula (stage 1) is the only formula your baby needs for the entire first year. It is based on whey protein, which is more similar to breast milk and easier to digest than casein-based alternatives.
Brand does not matter. It doesn't matter which brand of formula you use; they are all very similar and you don't need to be brand loyal. All UK first infant formulas meet the same nutritional standards and are regulated under the same legislation.
What you do not need:
- Follow-on milk (stage 2) — not recommended for babies under 6 months and unnecessary throughout the first year. Exists primarily as a marketing product because stage 1 formula advertising is restricted.
- Hungry baby milk — casein-based, harder to digest, no evidence it reduces feeding frequency
- Comfort milk, anti-colic milk — no evidence of benefit over standard formula for healthy babies
- Toddler or growing-up milks — not recommended; full-fat cow's milk from 12 months is appropriate
How to make formula safely
Powdered infant formula is not a sterile product. The preparation method matters — the goal is to use water hot enough to kill bacteria (principally Cronobacter sakazakii) that can cause serious illness in newborns.
How much formula — and when
Formula feeding should follow your baby's hunger cues — not a fixed schedule. This is called responsive feeding and is recommended by NHS and UNICEF Baby Friendly Initiative. A baby who is fed in response to hunger cues will regulate their own intake appropriately.
Amounts as a rough guide
Every baby is different, but NHS guidance provides this framework:
| Age | Amount per feed | Feeds per day |
|---|---|---|
| Day 1–2 | 5–10ml | 8–12 (very small, very frequent) |
| Day 3–7 | 30–60ml building up | 8–12 |
| 1 month | 60–120ml | 6–8 |
| 2–3 months | 120–180ml | 5–6 |
| 4–6 months | 150–200ml per kg/day total | 4–6 |
After the first week, a rough guide is 150–200ml per kilogram of body weight per day until around 6 months. But always follow your baby's cues first — these figures are guides, not targets.
Responsive bottle feeding in practice
- Feed signs to watch for: rooting (turning head and opening mouth), hands to mouth, increased alertness, small sounds — before crying, which is a late hunger cue
- Hold baby in a semi-upright position, keep feeds social and calm — limit the number of different people who feed your baby in the early weeks while you establish cues
- Use paced bottle feeding technique — tilting the bottle to allow pauses and letting your baby control the pace
Is my baby getting enough? — the reliable signs
This question causes more anxiety than almost any other in the newborn period. The good news is that the reliable indicators are objective and measurable — they are not about behaviour, which is notoriously misleading.
Nappy output — the most reliable guide
| Age | Wet nappies per day | Poo nappies |
|---|---|---|
| Day 1–2 | 1–2 (dark meconium) | 1–2 (black/dark green) |
| Day 3–4 | 2–3 (transitional) | 2+ (greenish-brown) |
| Day 5+ | 5–6 heavy wet nappies (pale yellow urine) | 2+ (yellow, loose for breastfed) |
| Week 2+ | 6+ heavy wet nappies | Variable (formula-fed may go 1–2 days) |
Weight
- Some weight loss in the first days is normal — up to 7% is common, up to 10% is the acceptable threshold
- Most babies are back to birth weight by day 10–14
- If weight loss exceeds 10%, or regain is not happening, seek same-day feeding support — this is a clinical issue, not something to manage alone
When to contact your midwife today
- Fewer wet nappies than the guide above
- Weight loss greater than 10% of birth weight
- Not back to birth weight by day 14
- Baby consistently very difficult to wake for feeds
- You are not confident feeding is going well — that feeling is worth acting on
Combination feeding
Combination feeding — using breast milk and formula together — is a valid and widely-used approach. It is not a failure to breastfeed and it is not the worst of both worlds. For many families it is genuinely the best fit.
There are two important things to know:
Breast milk supply is demand-driven. Every formula feed given replaces a breastfeed that would have stimulated supply. If you want to maintain breastfeeding alongside formula, it helps to introduce formula gradually (rather than replacing multiple feeds at once), to continue offering the breast regularly, and to express if you miss a feed. Supply usually adjusts to the new pattern within a few days.
If combination feeding is introduced because of breastfeeding difficulties — pain, latch problems, perceived low supply — addressing those difficulties with proper support will usually make a bigger difference than adding formula. Formula supplements can buy time and reduce pressure while you get help, but they work best when combined with proper breastfeeding support rather than as a substitute for it.
If you are thinking about stopping breastfeeding
Stopping breastfeeding before you want to is one of the more common and least-supported experiences in early parenthood. Around 81% of UK mothers initiate breastfeeding, but rates fall sharply in the early weeks — and surveys consistently show that most people who stop before they intended to do so did not want to stop.
The most common reasons — pain, latch problems, concerns about supply, exhaustion — are almost always addressable with the right support. Getting that support as early as possible, before difficulties escalate, makes the biggest difference. If you are struggling, seek help today rather than deciding to stop first.
If you have sought support and feeding is still not working, or if you choose to stop for any reason, that decision belongs to you. Any amount of breastfeeding carries some benefit. Stopping does not undo what you have already given your baby.
Formula is a safe, nutritionally complete way to feed a baby. Breastfeeding has genuine, evidence-based benefits — particularly for protection against gut and respiratory infections — that formula cannot replicate, because breast milk contains antibodies and living components that formula is not able to include. However, the magnitude of these benefits at the individual level in a UK context is often overstated. Formula-fed babies are well-nourished and the vast majority thrive. The most important thing is that your baby is fed — by whatever means works for your family.
In the first 24 hours, newborns need only 5–10ml per feed. After the first week, a rough NHS guide is 150–200ml per kilogram of body weight per day, spread across multiple feeds. Always follow your baby's hunger cues rather than a strict schedule — responsive feeding is recommended by NHS and UNICEF BFI. Weight gain and nappy output are the most reliable indicators that feeding is going well.
Track nappy output and weight — not behaviour. From day 5, a well-fed baby should produce at least 5–6 heavy wet nappies per day. Most babies are back to birth weight by day 10–14. If nappy output is lower, weight loss exceeds 10%, or you have concerns, contact your midwife the same day.
No. First infant formula is all your baby needs for the entire first year. Follow-on milk, hungry baby milk, and toddler milks are unnecessary products not recommended by NHS, UNICEF, or First Steps Nutrition Trust. At 12 months, babies can move to full-fat cow's milk.
Yes — it's a valid and widely-used approach. Be aware that every formula feed replaces a breastfeed that would have stimulated supply, so introduce formula gradually if you want to maintain breastfeeding. If you are combination feeding because of breastfeeding difficulties, seeking support for those difficulties first usually makes the biggest difference.