When did your stop growing during pregnancy?

Ok, I wasn't exactly small to begin with (34 D) but during my first few weeks of pregnancy I ended up in 34 F bras. I'm now almost 17 weeks and the F cup is getting a bit snug! Are my s going to continue growing right to the end or do they settle down during the second trimester? My back is killing me, partly because of the size of my stomach but I'm sure my being so huge has got something to do with it too. I'm wearing really good supportive bras but how big are they likely to get?