Reddit mentions of Save a Bra Soft Back Bra Extender 3 Pk

For the time being, I would recommend getting bra extenders. They sell them at most maternity shops, but also at joanne fabrics or similar. They look like little extensions.

She can also buy a few nursing bras, but I would caution against this. She's got bigger boobs now - they are going to get a lot bigger still when she's nursing. (I went from a B before, to a C during pregnancy, to a DD when nursing, and settled on a C after both of my kids).

I would highly highly recommend a few sleeping bras (I had some similar to this - they give enough support for her boobs not to hurt while sleeping, and are great for sleep-nursing after the kid is born.

Her best bet is going to be bras without an underwire, and with a certain amount of stretch to them. (Edit: Stretch is important - her boobs are going to continue to change and towards the end she may want to fit absorbent pads in there in case she leaks as well.) She may want some with light padding for cover, but not too much, because they are going to be bigger than she's used to already, and she probably wont want to accentuate that.

Also, I would recommend easily washed bras - ones that you don't need to worry about drip drying, etc. (this goes back to simple cotton, no underwire) because if she's anything like me she will sweat a lot. Its just part of pregnancy.

As for other things that help - 100% get a belly band! Worth every penny.

Its just a stretchy piece of fabric, but you can wear it doubled over unbuttoned pants (helpful again in the weeks after pregnancy). And then towards the end of pregnancy, i would wear it all the way up to help support my stomach. I recommend getting one in black, white, and maybe another color. The white was great to wear over my belly when i was 8-9 months, because it covered what i called "belly cleavage" - where the shirt hangs down from your belly button, and your pants are under your belly, so you have bare skin exposed to air.

Target has a belly band that they sell - its a little bit thinner material than the bellaband one though. Also, if she doesn't mind a seam, lots of people make them and sell them on ebay / etsy, etc. - they aren't quite as stretchy and supportive, but they cover up which is really the main function of them.

Edit 2: I can't stress enough not to spend a lot of money on bras now. A few temporary ones to get you till the baby is here, and wait until the baby is here to buy nursing bras. I spent a lot of money on bras I was never able to wear because they were too small for me when i was nursing. There just isn't a good way to gauge it. Also what she finds comfortable now - before she had kids - will be completely different from after, because the actual structure of her boobs is going to change. I wouldn't dream of wearing a bra that wasn't underwire with light padding now, but I used too all the time. What used to be flattering for me isn't anymore.

Would a bra extender help in the short term? I think you can get them on Amazon for under $10.

Edit - I actually found this for 99 cents!