Benadryl during labor?

This is way premature, but I was thinking about whether using Benadryl
during early labor would be a good way to get some rest while I still can.
I have chronic insomnia, so I'm using Benadryl a couple times a week now to
get to sleep. I can see myself being too excited once contractions start to
get any sleep, and of course that's exactly when you'd want to be getting
some rest! I'm hoping for an intervention-free birth with immed. bf
afterward, so I can see Benadryl having pros/cons. Pro, get some sleep
early on and be rested for the hard part and it's not like taking Demerol or
something. Con, might make the baby sleepy at birth?
Anyone know how long the Benadryl might take to wear off in the baby? I'll
be asking my midwife, but I like getting other opinions/experiences before I
bring up an issue so I know better what to ask about.

Thanks,
Amy