Taken from: http://www.positive.org/Home/faq/pregnancy .html

Can I get pregnant during my period?

Yes, but it's very unlikely. Women do not ovulate during their period. However, eggs may live for 2 days and sperm may live for 5-7 days inside a woman's body. They could finally meet up during menstruation, but it's rare

It's very rare, but it could happen, if you ever want to talk just PM me

It can happen. A friend of mine had sex the last day of her period. She was also under the impression that she could not become pregnant on her period. She delivered a beautiful little girl just last week (Britian ). Her period would last for about 7 days. So say she had sex on the seventh day and sperm can last say 5 days. That takes you to day 12. If you have a 26 day cycle thats right on the nose. Just my two cents.