Well, you can't get pregnant while you're pregnant of course. But since sperm can live in the vagine from 3 to 7 days it may be possible. With that said, I really don't think so. I doubt that the pregnancy vaginal fluid would be conductive for sperm to live. And even if it was, right after pregnancy is over, I really don't think it could happen. For two reason, the first is what erin said, and the second is because even after the birth of the baby, you bosy still has pregnancy hormones. I think this may be why it takes a couple of day for the actual milk to come in.