Generally cramps are due to hormones. Some cramps can occur if the menstruation has clots as well, because the flow doesn't come through the cervix easily.
Some other causes can include, Endometriosis, Uterine polyps, Pelvic infection, Ovarian Cyst, Adenomyosis.
If they are severe you may want to talk this over with your doctor.
Hope this helps, If you need anything else please feel free to ask. If you found this helpful don’t forget to click the *accept* button!
