New bra?

Cara • Expecting our first baby Jan 1st 2016! Married my best friend after 8 years together 10/10/14.
How far along into pregnancy do most women end up needing a new bra? I am only 6w1d and I already notice that my bra doesn't really fit anymore. The cup size seems to be too small. I know I will continue to grow in size as time goes on so not sure what to do now.