Could aspirin and vitamin c be used to prevent pregnancy?

No.: Neither Aspirin or vitamin c or combination of both will prevent pregnancy. To prevent pregnancy, most commonly, you have to prevent fertilization either by physically blocking the sperm from reaching the egg (this is condoms, diaphragms, cervical caps work). Or, by preventing ovulation (this is how traditional hormonal birth control works). Aspirin and vit c will not prevent pregnancy!