hi PPS!!
Good luck first of all!
I think the short sleeved nightie is a good idea to start with. I was in my normal clothes for an hour and a half, decided I ought to change when they said I was in established labour so went upstairs (started another ctx of course, stairs = bad idea in labour!) and put on an old cotton thing I never wore for DS1 but intended to...I think it's victorian, came from boot fair, looked like it must have seen lots of women through whatever (but clean, just old I mean!)
Anyway a few minutes later I got in the bath and so that didn't last. After about 2 more ctx I got out and went into transition, so was beyond any effort at clothing and TBH it felt much better having nothing in the way, they could access whatever they needed to and things were very fast & furious by then.
They couldn't see the baby's head anyway as I was kneeling on my heels by the bed, so a nightie would have made it even harder for them!
you really don't care by the end, two newish friends were present and I was lying around afterwards totally starkers, they didn't seem to mind, they've both got bodies, both given birth..I do feel a little uncomfy with the idea in retrospect but am naturally shy
Deffo not pyjamas though. You'll need too much help to get them on and off!!! And how can anyone reach their socks???