The short answer
A little milk coming back up, from a baby who is happy and gaining weight, is normal. The AAP says all babies spit up; it usually starts around 2 to 3 weeks, peaks at 4 to 5 months, and goes away by 9 to 12 months for most. Call your doctor if your baby refuses feeds, cries or arches in pain, isn’t gaining weight, or the spit-up is green or has blood in it.
What’s normal
The NHS says it’s common for a baby under 1 to bring up a little milk during or after feeds. The AAP calls it reflux (GER): stomach contents coming back up into the food pipe, sometimes out of the mouth. A baby who is happy, feeding well and gaining weight usually needs no treatment, according to the NHS.
When it starts and stops
The AAP says it usually begins at about 2 to 3 weeks, peaks between 4 and 5 months, and for most full-term babies is gone by 9 to 12 months. Sitting up and starting solid foods tend to help. The NHS puts it similarly: it improves by around the first birthday.
What can help
From the NHS:
- Check your breastfeeding position or bottle technique.
- Hold your baby upright during feeds and for as long as you can after.
- Burp them regularly during feeds.
- Always lay them flat on their back to sleep, and don’t raise the head of the cot or Moses basket.
That last point matters: propping the cot isn’t a safe fix. If you’re worried about how much your baby is taking, see the baby feeding chart.
When to call the doctor
The AAP lists these as reasons to call your pediatrician:
- Refusing to feed
- Crying or arching the back during feeds, as if in pain
- Blood, or green colour, in the spit-up
- More frequent or heavier spit-up
- A swollen, distended or hard belly
- Wheezing or coughing
- Poor weight gain, or fewer wet and dirty nappies
The NHS adds forceful (projectile) vomiting, green or yellow vomit, blood in poo, a very high temperature, dehydration signs or a baby who can’t be comforted, and says to get urgent help for them. Read the NHS page before deciding to wait.
Spit-up or vomit?
The difference is mostly about force and amount. The NHS describes spit-up as “a little bit of milk” that comes back easily, with no distress. Its warning sign is projectile vomiting: being sick with more force than usual. The AAP’s list includes a spit-up that gets more frequent or more intense. If a feed comes up in a large amount, again and again, or shoots out, treat it as vomiting and call your doctor.
Reflux and safe sleep
It’s tempting to prop a baby up to sleep. The NHS says not to: always lay your baby flat on their back, and don’t raise the head of the cot or Moses basket. Upright time belongs to the time after a feed, while you’re holding them. Then put them down flat. More on the basics in the AAP’s safe sleep guide.
What to tell the doctor
Notes help. Jot down how often it happens, roughly how much, how soon after feeds, and anything else you’ve noticed: arching, coughing, refusing a feed, fewer nappies. Ask about weight gain at the next checkup. The NHS says to see a GP if the symptoms don’t improve, if reflux starts after 6 months, if your baby isn’t gaining weight, or if your child still has it after 1.
At night
Spit-up at night is one reason parents check often. A monitor lets you hear a cough or a fuss without turning the light on: see sound detection for what the app listens for. It’s a prompt to go and look, not a safety check: if you hear choking or struggling, go to your baby and get urgent help.
Spit-up, quick answers.
How much spit-up is too much?
The sources give no amount. The NHS describes a little milk. The AAP says to call your pediatrician about an increase in how often or how much, or if there’s poor weight gain.
When does baby reflux go away?
The AAP says for most full-term babies it’s gone by 9 to 12 months. The NHS says it usually improves by around 1 year.
