What Happens To Sperm During Period Sex During Pregnancy...asked WRONGLY B4(sorry)..how Does The Sperm Come Out If Not Trough Period?

Sex during pregnancy...asked WRONGLY b4(sorry)..how does the sperm come out if not trough period? - what happens to sperm during period

I mean, right after sex when ur pregnant (which, of course not undo lost time or sperm)
And he? How it comes the time is usually once a month .....?