I haven't fainted at all, I wouldn't worry about it, stay very hydrated and sit down if you feel dizzy, keep snacks on you like peanut butter cups or crackers and if you feel dizzy drink some water, eat a cracker and sit down, you'll be fine! :) Most women don't faint while pregnant but if you do it's not a huge deal.
I didn't faint once and I am 26wks 3ds. I do have spells of dizziness or light headed. But usually because I might get up way too fast. But every pregnant woman is different.