OK..so I have a question. I had sex during my period and pretty much at the end of my cycle. I am with my boyfriend and we don't use protection he just always pulls out and we have been doing this for about a year. This weekend we decided that we would just take a chance as I was on my period and we don't think I can get pregnant. I know you can, I guess we were just testing our luck. What I need to know is when could I know if I am pregnant? Could I use a pregnancy test 7 days after we had sex and check? How does it work?
You can only get pregnant if the sperm can survive until you ovulate. Ovulation only takes place 12 to 16 days before your next period. Sperm will most likely survive 3 days inside you with another 2 days added for just in case he's got wonder-sperm so make it 5 days.
So you can see that the chances of getting pregnant from period sex is largely theoretical for women with normal cycles. Unless you have a totally messed up cycle or cycles shorter than 21 days, it is not likely at all. If you are very young your ovulation can also be a bit erratic just after you started having your periods so that is also a dangerous period of your life to be taking these chances.
After ovulation a fertilized egg will travel along for about another 10 days before it implants in your uterus. About 4 days later you will miss your period if the egg implanted successfully. 7 days after your missed period you can expect to get an accurate pregnancy test if you follow the instructions.