The pain on both sides of the pelvic buttocks during pregnancy may be caused by changes in hormone levels, compression caused by the enlarged uterus, osteoporosis and other reasons. 1. Changes in hormone levels: changes in hormone levels in the body after pregnancy, resulting in ligamentous relaxation of the pelvis and spine, and excessive localized pressure, which can cause pain on both sides of the buttocks and pelvis. Usually pay more attention to rest, try to avoid excessive exertion and aggravate the symptoms. 2. Increased uterine compression: with the increase of pregnancy and fetal development, the uterus will gradually increase in size, causing greater pressure on the pelvic area, affecting the local pelvic blood circulation, and there will be pain on both sides of the buttocks and pelvis. 3. Osteoporosis: After pregnancy, the demand for calcium by the mother and the fetus increases, and insufficient supplementation of calcium may cause osteoporosis, which may lead to the symptoms of pain in the buttocks and pelvis. There are many causes of pain in the pelvic region during pregnancy, and if the symptoms are severe, it is recommended that you seek medical attention in a timely manner.