The following symptoms are common when lumbar muscle strain occurs during the menstrual period: First, when feeding the baby, sitting for too long will cause lumbar soreness, bending over to hold the baby or standing position for too long will also cause lumbar soreness, the soreness is often recurrent, and the soreness is mainly concentrated on both sides of the lumbar spine and the edge of the iliac bone. Secondly, when bending over to hold the baby, there can be a limitation of lumbar spine forward flexion activities, resulting in the inability to bend over. The above symptoms are closely related to the shifting of the center of gravity during pregnancy, resulting in overloading of the lumbar spine and lumbar muscles, as well as poor posture in feeding the baby after delivery. The symptoms of lumbar pain can be relieved after correcting the poor posture of the lumbar region, and after massage and bed rest.