It's very unlikely. There's only a certain time during your cycle that you can get pregnant, for around 24 hours when the egg is released (is it around day 14?). However, sperm can survive inside for a few days until the egg is released if before. Anyway there should be enough time between the period and ovulation for you to not get pregnant.....and to be honest.....good luck finding a guy who would have sex during a period.