Anytime you're having unprotected sex, there's always a chance that a woman can get pregnant. Pregnancy requires sperm and egg to meet up together so a woman needs to be during her most fertile time of the month, which is usually 6 days out of the month; 5 days leading up to ovulation and on the day of ovulation. For most women, ovulation happens 12-16 days before her period's going to start. So a woman is usually most fertile for a week to a week and a half after her period has ended generally speaking, if you don't want to count each and every single day. So if you have unprotected intercourse during this time, then there's a high probability that a woman can get pregnant. Now, you mentioned that your girlfriend is supposed to start her period in about five days or so. If you've had intercourse any time leading up to this, there's always a chance that she could get pregnant. But as for the mechanics of it all, in order to get pregnant, semen needs to be inserted inside the vaginal canal where the egg and sperm can then meet. So if that did not happen, then the chances of her getting pregnant are slim. But if that has happened, the chances of her getting pregnant are great. So it would be best for you and her to just wait until her period is supposed to start and if she's late, then take an over-the-counter pregnancy test and if it's positive, congratulations to both of you! If it's negative and she still doesn't start her period, then tell her to wait about 5-7 days. Take another test and then maybe at that point, it will be positive if she is indeed pregnant. If she continues to not have a period or she's concerned about anything, it would be best for her to follow up with her doctor and they can decide if further investigation or treatment is warranted. If you have any other questions for me, feel free to ask them on our Facebook page at facebook.com/intermountainmoms and recommend us to your friends and family, too.