Hasn't happened to me, although i've had a couple of close calls. I faint with the best of them!! My sister was telling me that she had a couple of fainting spells with her first baby. Your blood pressure drops naturally and so you can get dizzy easier. Baby turned out fine. The good thing about fainting is that you kind of collapse "softly" ... depending what you land on, of course!! Falling over is a little more painful. Either way, baby is almost certainly OK. I'm guessing you're not due in May this year (!), so there's still loads of fluid around to cushion him/her.

Someone told me pregnant women have been falling over for centuries and the babies come out just fine at the end! Good luck with your doctor and make sure you rest lots and don't stand up too quick or for too long in the heat ((HUGS))