Why does my baby bottle leak past the teat?

A baby bottle nearly always leaks for one of two reasons: the parts are not sitting correctly, or pressure has built up inside. Loosen or tighten the ring a little, check the teat and let warm milk release its pressure. That solves it in most cases. Below you can work through the causes one by one.

The screw ring is too loose or too tight

A ring that sits too loose lets milk run along the rim. A ring that sits too tight stops air from getting in. The teat then pulls itself flat and releases a squirt with every suck.

So tighten the ring firmly, but never with force. Check that the teat sits straight in the ring and does not fold anywhere.

Pressure has built up after warming

Warm milk expands and builds pressure inside the bottle. As soon as you tip the bottle, milk sprays past the teat. Leave the bottle to stand without the teat, so the heat can escape.

Does that not help? Hold the bottle upright, press the teat down with your finger and turn the bottle over. Release your finger once the teat is full of milk. Mix the feed gently instead of shaking it hard.

The teat is worn or the size no longer fits

Silicone softens and widens after months of daily use. A stretched teat no longer seals and starts to leak. Replace teats regularly and check each one for small tears before a feed.

A size that is too large also causes mess, because more milk flows than your baby can swallow. Read how to know when your baby needs a larger teat size. Is your baby restless during feeds as well? Our article on uncomfortable drinking from the bottle takes you further.

Check every separate part

A bottle has more parts than you might think: ring, teat, cap and sometimes a valve that lets air escape. If one part is missing or sits crooked, the bottle leaks straight away. Always put the parts back together completely after cleaning.

Something lost or damaged? You will find spare parts for your baby bottle in our shop. Still leaking after all this? Have a look at our baby bottles for one that suits you better.

One practical tip: lay all the parts out separately to dry. You then spot a missing piece before the next feed starts.

Frequently asked questions

Why does my bottle only leak when it is warm?
Because of pressure from the warm milk. Let the bottle stand without the teat and the leaking stops.

How often should I replace a bottle teat?
As soon as you see discolouring, tiny tears or a stretched shape. Check each teat by pulling gently before use.

Is a leaking bottle harmful for my baby?
No, but your baby gets less milk and swallows more air. So it is worth fixing quickly.