For most women, hormonal contraceptive methods—the pill, injectable, or implant—have helped them experience less painful periods than those who don’t use these kinds of methods.

The reason for this is because hormonal contraceptives make the lining of the uterus thinner, which makes periods lighter because there is less to shed.

One reminder regarding the injectable: some women may experience more days of spotting or bleeding, but periods are generally lighter and less painful.

Source:

https://www.webmd.com/women/qa/can-birth-control-pills-help-stop-menstrual-cramps