During menstruation, the common causes of swelling and pain in the calves are as follows: 1. Mainly because the pelvis is congested during menstruation, the blood circulation in the lower limbs is affected accordingly, so there will be swelling and pain in the calves, this is the first reason, it is recommended to give proper rest, and soak your feet in hot water every night to promote the blood circulation, which will improve the symptom of swelling and pain in the calves.2. There is also a possibility that there is a tumor in the pelvis. Tumor, during menstruation, due to pelvic congestion, the tumor is relatively large, causing poor venous blood flow in the lower limbs, resulting in calf distension and pain, through ultrasound, gynecological examination can often make the corresponding diagnosis. If there are indications for surgery, surgery is recommended as soon as possible. For pelvic tumors, blood can be drawn to check gynecological tumor markers before surgery to understand whether there is a possibility of cancer before preparing for surgery.