I think many pregnant women get to a point where sleeping without a sleep bra or some other sort of support is way too uncomfortable. Having my increasingly larger and more sensitive parts unrestrained while I sleep definitely has become intolerable for me--but its so dang hard to find a well-designed maternity/nursing sleep bra for larger busts (D+)!
Lamaze's Cotton Spandex Sleep Bra ($18) is definitely not the solution to my problem. While it is soft and comfortable and supportive enough while sitting upright, sleeping in the bra is a whole different situation.
The deep v-neck crossover design--which is designed to make for easy nursing--actually makes is such that when you lay in bed your boobs simply fall out one side or another. Aggravating! Now, if you have super perky boobs (real or constructed) that stay put no matter what, I assume you won't have a problem. But, this mama is just not that lucky.
I've run into this problem before, though, with crossover/wrap-style sleep bras. The only solution, perhaps, for women with larger busts like me is to go for a different style of sleep support and maybe sew up the v-neck opening of your wrap-style bras so they don't go to waste.
My favorite sleep solution so far has to be Bravado's Essential Nursing Tank. No, its not a bra, and it can run up to $60 depending on the size and color you want/need, but your boobs aren't going anywhere in this baby thanks to the comfy built-in wireless bra and the adjustable shoulder straps. If you're lucky, you can find the tanks for sale on discount sites like Zulily or Baby Steals, and Amazon has some of the less popular colors on sale for lower prices.
I'll most likely be living in my Bravado Nursing Tanks once the baby arrives in the next couple of weeks, but I will still be on the hunt for good sleep bras and nursing bras that I can wear outside the house. Please feel free to post your suggestions below!