4 month old drinking less

[alwaysleeping]

My DD has been drinking around 100ml at each feed the last 2/3 weeks. Sometimes she will have more, even finish the whole bottle but most of the time it's only approx. 100ml. She usually drinks between 150-200ml.
Is this common for a 4 month old?
She has been teething the last couple of weeks and is normal in herself otherwise.

Maybe she can start to go longer between feeds? Is she asking for the bottle or you are just giving her one every 2/3 hours ?

We tend to feed her every 4 hours but sometimes she is hungry sooner than this so we will feed her. She opens her mouth wide and grabs onto the bottle but then will only have about 100ml