Although I am 10 weeks and already have a tummy showing significantly enough to wear maternity clothes, my boobs have barely changed. I have heard that it isn't good to wear underwires during pregnancy which is all I have.

What I want to know is how soon should I be looking at maternity bras? I'm scared if I go out and get one now to fit me or even one size bigger, that in two months time I will need to buy another one, and then 1 month after that I will need another. They aren't cheap and with a new baby on the way I can think of more practical ways of spending my money than on bras that last me 2 months! When are they supposed to change size and shape significantly? Should I go and get some now, or wait a little longer?

Thanks for your help in advance!!