I headed to the birthing unit in a nightie, undies (those awesome ones that come in a pack of 8 which your mum bought you when you were 8!

) and a singlet.. got rid of my undies while I was waiting for the pool to fill, then off with the nightie and I laboured and birthed in just my singlet... Oh and I had, DH, Mum, MIL, student midwife & MW obviously in the room and FIL joined in 2 minutes after Nova arrived. And yes he has seen alllllllllll of me!!
But honestly, I couldn't care less at the time, I was only concentrating on one thing and so was everyone else
My advice - wear whats comfortable