Can a girl get pregnant on period ever?

Almost never!: It is nearly impossible to get pregnant during your period. From when your period starts, count 14 days ahead. If you are ovulating normally with a 28-day cycle, then you are most fertile day #14 after your period started. If your cycle is longer or shorter, it can be much more difficult to tell. Talk with your ob/gyn about basal body temperature measurement to find when you are most fertile.