Sore legs during menstruation may be related to higher menstrual bleeding and obstruction of venous return in the lower limbs. 1. Higher bleeding: the problem of sore legs during menstruation may be caused by higher bleeding. When the amount of menstruation is higher, the number of red blood cells in the body will be relatively reduced, which will make the oxygen carrying capacity of the blood lower, and the supply of oxygen to the leg muscles will be poor, which will result in a lack of support. 2. Lower extremity venous return obstruction: some women will have lower extremity pelvic vein stagnation during menstruation, which will cause lower extremity venous return obstruction and leg discomfort. Sore legs during menstruation may also have other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.