If you have severe cramping from a menstrual period, exercise
can seem almost impossible. Endometriosis
can cause pain in your uterus a few weeks before your period starts. After physical activity and sex, the pain may be most noticeable. If you have an allergic reaction to exercise, cramping of the uterus is one of the many symptoms and can occur during or after exercising, according to the American Academy of Allergy Asthma & Immunology.