Between 70 and 85% of babies spit up milk daily starting around 2 months old — it's one of those things that causes more worry than it needs to, because it's almost always normal reflux, not an illness. But since it can look similar to other things, it's hard to know when it's just an extra bib and when it's worth real attention.
Why it happens
The lower esophageal sphincter — the muscle separating the esophagus from the stomach — is still immature in the first months. It opens more easily than it should, and some milk comes back up after a feed. It's not painful in most cases: think of it as new plumbing that doesn't seal all the way yet.
Reflux, spit-up or vomiting: how to tell them apart
The three words get used as if they meant the same thing, but they don't — and telling them apart helps you know when watching is enough:
| What it is | What it looks like | When to call | |
|---|---|---|---|
| Reflux | Milk moving back from the stomach into the esophagus; it may or may not come out | Often only noticeable as frequent spit-up | If any of the warning signs below show up |
| Spit-up | Milk that comes up and out effortlessly, usually after a feed | Small amounts dribbling from the mouth; baby stays content | If weight gain stalls or baby is very fussy |
| Vomiting | Forceful emptying of the stomach | Larger amounts, with effort, sometimes in a stream | If it is projectile, green or yellow, bloody or keeps repeating |
If what you're seeing looks more like vomiting than spit-up, see the guide to baby vomiting: when to worry.
When it's normal
Reflux doesn't need treatment if, besides spitting up, your baby:
- Is gaining weight as expected at pediatrician checkups.
- Seems happy and active between feeds.
- Doesn't seem to be in pain or irritable while eating or lying down.
- The spit-up is gentle milk, not a forceful stream.
When to worry
Check with the pediatrician if you notice:
- Weight plateaus or doesn't go up at routine checkups.
- The baby refuses to eat or gets very fussy during or after feeds.
- Projectile vomiting — forceful, not simple spit-up — especially under 1 month old.
- Signs of dehydration: fewer wet diapers than usual, dry mouth, lethargy.
- Persistent cough, arching the back while feeding, or crying that always seems tied to eating.
What helps at home
- Shorter, more frequent feeds — instead of a few large ones that overload the stomach.
- Keep them upright for 20-30 minutes after each feed, avoiding lying them down right away.
- Burp thoroughly midway through and at the end of the feed, not just at the end.
- Avoid overfeeding — offer breast or bottle on demand, without forcing them to finish it.
- Skip tight clothing around the belly area.
How it changes with age
Reflux tends to be most common in the first months and generally improves as your baby grows: they spend more time upright, start sitting, eat thicker foods and their stomach matures. Most babies outgrow it around their first birthday.
Check with your pediatrician if it's still the same after age one, if it starts for the first time after 6 months, or if it's getting worse instead of better. In those cases your pediatrician will look into whether something else is going on.
Reflux and sleep: dos and don'ts
It's tempting to lay your baby down tilted or on their side "so they don't choke", but safe sleep recommendations are the same for babies with reflux:
- Do: back to sleep, on a firm, flat mattress, for every nap and at night.
- Do: hold them upright for a while after feeds, while they're awake.
- Don't: use pillows, wedges, rolls or positioners to prop them up in the crib.
- Don't: put them on their tummy or side because of reflux (see why tummy sleeping isn't recommended).
What to note down for the appointment
If you're going to see the pediatrician, a couple of days of logs beat any memory. The most useful things to bring:
- The time of each feed and the approximate amount.
- When the spit-ups happen and whether some feeds trigger more.
- How many wet diapers per day.
- How weight is tracking at checkups, using their growth curve.
- Whether they cry, arch or refuse the breast or bottle while feeding.
Feeding statistics — a real screen from the Alfonso app.
When you log every feed in Alfonso, the feeding stats show the daily average, the interval between feeds and the amount per feed — so you can see whether reflux gets worse with bigger or closer-together feeds, a common sign of overfeeding. If your baby also cries a lot at certain times of day, reading about baby colic may help.
Feeding history — a real screen from the Alfonso app.
Log every feed and see if it improves
Create your baby's profile in 30 seconds, no account or password needed, and note the time and amount of every feed — to see if reflux actually improves with changes, not just guess. Syncs automatically with your partner.
Frequently asked questions
Is reflux the same as vomiting?
No. Reflux is milk that comes back up effortlessly; vomiting is more forceful and in larger amounts — if it's projectile, check with the pediatrician.
How long does it last?
Most babies outgrow it by their first birthday. It usually peaks between 2 and 4 months.
Does switching formula help?
Sometimes, but it's not the first step — try it only on the pediatrician's advice.
Does reflux hurt my baby?
In most cases, no: many babies spit up and stay perfectly content. If your baby cries a lot while feeding, arches their back or refuses feeds, ask your pediatrician to check them.
Do I need to change my diet if I breastfeed?
Not by default. Any change to your diet is best made only if your pediatrician recommends it, after examining your baby.
Keep reading
ℹ️ This article is informational and doesn't replace a pediatrician's judgment. If you're unsure about your baby's reflux or feeding, always check with a healthcare professional.