It's extremely unlikely to ovulate during your period, although women who do have irregular periods, there is a possible chance that they can ovulate through what appears to be a period but is not in actuality.
However, it is still possible to get pregnant if you have sex during your period because the sperm can live in your body for up to 5 days... so if you have a short cycle, or you are actually not having a period but mid cycle spotting, then you can fall pregnant.