Baby Reflux and Silent Reflux: Signs, Causes and How to Help

Quick answer: Reflux is stomach contents flowing back up the oesophagus, and it usually settles on its own by around 12 months. Visible reflux brings milk up as a posset or vomit; silent reflux is swallowed back down, so the clue is distress without spit-up. Upright feeding, smaller feeds and winding help; babies should always sleep flat on their back. Call 999 or go to A&E for green vomit or blood in vomit; call 111 urgently for projectile vomiting or refusing feeds.

What parents need to know

If your baby spits up frequently, arches their back during or after feeds, or seems uncomfortable despite being fed, reflux could be the explanation. It's one of the most common infant conditions — affecting around half of all babies under three months to some degree — and for most babies, it's temporary and manageable.

What is baby reflux?

Reflux occurs when stomach contents flow back up into the oesophagus (food pipe). In babies, this happens because the lower oesophageal sphincter (the muscle that keeps food in the stomach) is immature and doesn't always close effectively. As it matures (usually by 12 months), reflux resolves on its own for the vast majority of babies.

Reflux is often called gastro-oesophageal reflux (GOR) when it's the normal, developmental kind. When it causes significant distress or other symptoms, it becomes gastro-oesophageal reflux disease (GORD).

Reflux vs silent reflux

In regular reflux, milk comes all the way back up and is visible as a posset or vomit. In silent reflux, the milk travels up the oesophagus but is swallowed back down before reaching the mouth — so there's no visible spit-up. This can make it harder to identify, because the visible clue is missing.

Signs of reflux in babies

• Frequent spitting up or vomiting after feeds
• Arching the back during or after feeding
• Crying and apparent discomfort during or after feeds
• Feeding difficulties: pulling off the breast or bottle, refusing to feed, or wanting to feed constantly for comfort
• Hiccupping frequently
• Wet or "gurgly" breathing sounds
• Unsettled or disturbed sleep (even so, always put your baby to sleep flat on their back)

Signs that may indicate silent reflux

• Distress during and after feeds without visible vomiting
• Swallowing or gulping frequently
• Hoarse or "raspy" voice
• Back-arching and apparent pain
• Refusing feeds despite apparent hunger
• Poor sleep and frequent waking

What helps with reflux

Feeding position

Keep your baby as upright as possible during feeds — ideally at a 45-degree angle. After feeding, hold them upright for at least 20–30 minutes before laying them down. Gravity is your friend.

Smaller, more frequent feeds

For formula-fed babies, smaller amounts more often reduces the volume in the stomach at any one time. For breastfed babies, shorter feeds or more frequent feeds may help. Avoid overfeeding.

Winding well

Make sure you wind thoroughly during and after feeds. Trapped wind can make reflux worse.

Thickened feeds (formula)

Anti-reflux or "comfort" formulas contain thickeners that make the milk harder to bring back up. Speak to your GP or health visitor before switching: these aren't suitable for all babies.

Safe sleep

Always put your baby to sleep flat on their back, not on their side or front, even if they have reflux. Do not raise the head of their cot or Moses basket (for example with a rolled towel under the mattress), and never prop your baby on pillows or inclined devices.

Medication

If lifestyle measures aren't enough and your baby's reflux is causing significant distress or affecting weight gain, a GP or specialist may suggest an alginate medicine for a short trial, or a medicine that reduces stomach acid (such as omeprazole). Ranitidine is no longer available in the UK. NICE advises that acid-suppressing medicines should not be used when bringing up milk is the only symptom. Only give your baby a reflux medicine that a doctor has recommended, and ask a pharmacist if you are not sure how to give it.

Frequently asked questions

How can I tell if my baby has silent reflux?

Silent reflux has no visible spit-up because the milk is swallowed back down. Look instead for distress during and after feeds, frequent swallowing or gulping, a hoarse or raspy voice, back-arching, refusing feeds despite hunger, and poor sleep.

When does baby reflux go away?

Reflux happens because the muscle keeping food in the stomach is still immature. As it matures, usually by 12 months, reflux resolves on its own for the vast majority of babies.

How long should I hold my baby upright after a feed?

Keep your baby as upright as possible during feeds, ideally at a 45-degree angle, then hold them upright for at least 20–30 minutes before laying them down.

When should I see my GP about baby reflux?

Call 999 or go to A&E if your baby has green or yellow-green vomit, blood in their vomit or vomit that looks like ground coffee, is under 3 months old with a temperature of 38°C or higher or 3 to 6 months old with a temperature of 39°C or higher, has a weak, high-pitched or continuous cry, or has any of the other emergency signs listed above. Ask for an urgent GP appointment or call NHS 111 if they have yellow vomit, blood in their poo, are projectile vomiting, have a swollen or tender tummy, are refusing to feed, or have any of the other urgent signs listed above. See your GP if they are not gaining weight, reflux is not improving, it starts after 6 months, or it continues after their first birthday.