My usual bras feel so tight and uncomfortable now, especially at night. I sleep so much better without one but then I worry if going without will cause sagging or some problem. What did you ladies do?
It's your choice really. But your breasts grow a lot so a comfy cotton non wired bra makes a big difference, especially later when they get heavy. At night I switched to a soft sleep bra and it helped.
I felt so much more comfortable once I switched to soft maternity bras. My normal ones got too tight and the underwire was poking me. It's not compulsory but a good supportive one really helps with the heaviness.
There's no must here, do what feels comfortable. Just avoid tight wired ones that leave marks, your body is changing and it needs room. Soft and supportive is the way.
I'd suggest investing in nursing bras a bit early, like in your last trimester. You'll be living in them after delivery anyway, and they support nicely without digging in.