How many ladies have gotten pregnant right before their period was due?

Shannon
So we had a little slip up on the 4th. My period was due today. I know my mom & one of my sisters have gotten pregnant before their period. My app says I had 5% chance of getting pregnant. I wanted to see out there how common this would be? I doubt I am pregnant. My period has been several days late before. We are getting married in October, silently I am praying that I am pregnant, and he is too.