Can masterbation cause heavy bleeding of menstrual cycle?

No: Masturbation can bring on your cycle a little bit early because of the mucle contractions, but it can not increase the flow.

Shouldn't : Unless you're doing something aggressive or traumatic, there should be no overt correlation between masturbation and menstrual flow. Masturbation *during* menstruation could theoretically cause the appearance of heavier flow but likely not actual increased volume of bleeding.