Period sex fertility

Anna

I know you can get pregnant at any point in your cycle and that sperm live for like a week. I’m just curious, if you have sex the day your period starts, like you’ve already started bleeding, and the sperm meets the egg, and it becomes a blastocyst, will your period stop? Will you have a miscarriage? Will you get pregnant? Or will the egg just leave the body as normal because it’s barely anything yet?