I had to do a 5 hour one once (not while pregnant) and was embarrassed to go back to work because of all the nasty bruises. The woman at the lab was brutal and used needles twice as big as she needed and stuck me in a new spot for each draw. Ugh.
I had a huge bruise from my one hour then when I went back for my 3 hour a few days later I got a couple more little ones. When I got home and showed DH the first thing he said was that I looked like a drug addict...nice.
Re: i have the most horrific bruise from my glucose blood draw.
I didn't bruise at all but you could kind of see where they poked me if you were looking closely.