I went to myer twice during pregnancy to get fitted as my cup size went up again between 20 weeks and 36 weeks, so don't buy too many bras early on in case this happens to you! At the second fitting I got the ugliest bra (triumph) but it fits well and it gives me way more support so no uniboob/sagging etc! Myer also have the Chloe & Lola brand in maternity which are really nice non-ugly bras, I'm going to go back and try them when my feeding settles so I have some nice bras too (hope they fit!).
Oh also I've gone from a c to a dd between getting pregnant and birth. HTH!