What happens if you're on your period and play with yourself do you get pregnant?

Sperm & pregnancy: Masturbation does not cause pregnancy. The only way to become pregnant is from a man's sperm. When having sex condoms can prevent unwanted pregnancies and venereal disease.

No: Pregnancy is caused from sperm coming in contact with an egg. The activity you described will not result in contact between those cells, so I think you are not at any risk.