Yes! definitely. Ive never had a completely flat stomach, but usually if i breathe in its flat.. so in my first pregnancy i kept breathing in to see when i had an "actual" bump.. i remember it was around 18 weeks i breathed in and my tummy didnt go flat.
Im only 9 weeks and when i breathe in now my tummy sticks out a fair bit. I dunno if its just bloat though.. how can something the size of an olive make such a difference? Unless my uterus is now like a sack of spuds rather than the lovely, tiny, slim thing it was before it housed a giant baby...