Are you able to fall pregnant 1 day before your period starts?

Not if her period...: Not if her regular period actually happens on the next day. Have one's true, regular period means NOT pregnant. A woman with very regular periods is not likely to get pregnant 1 to 7 days before the day her period is expected to begin. There is a possibility of pregnancy, if for some reason she ovulated late that cycle (meaning that her next period would have come later than expected).