I wore tracky pants, a breastfeeding singlet (as was my "uniform" in those last few days) & one of DH's tshirts.
I lost the pants fairly early on. Was sooo hot but kept the tops on until DS was born & the midwife took them off me. Said to DH "Couldn't you see how hot I was? Why didn't you take them off me earlier?" I felt like I was sweating buckets but he said I looked normal.