Can penetration push menstrual blood back inside or block it from flowing?

Menstrual bleeding is a natural process where the body sheds the lining of the uterus. The references provided do not directly address whether penetration can push menstrual blood back inside or block it.

• Reference 1 discusses coitus and menstruation in perimenopausal women, but does not mention any issues related to penetration affecting menstrual flow.
• Reference 2 is about the effects of a contraceptive implant on menstrual patterns, which does not relate to the mechanics of menstrual blood flow during penetration.
• Reference 3 examines flax seed ingestion and its effect on the menstrual cycle, without discussing penetration.

From these studies, we can infer that the natural flow of menstrual blood is not significantly affected by penetration. If you have specific concerns or experience unusual symptoms, consulting a healthcare professional is recommended.