The muscle pain on both sides of the buttocks in the 5th month of pregnancy may be caused by nerve compression and muscle strain, etc. Pregnant women need to clarify the specific causes and carry out treatment of the causes. 1. nerve compression: the uterus increases in the 5th month of pregnancy, which will compress the pelvic tissue as well as the pelvic bone, which in turn may compress the sciatic nerve and cause muscle pain on both sides of the buttocks. In addition, when the uterus increases in the fifth month of pregnancy, the amniotic fluid increases and the load on the lumbar spine increases significantly, which can easily lead to lumbar disc prolapse, thus compressing the nerves and causing pain in the hip muscles; 2. Muscle strain: pregnant women may often sleep and rest on their backs in the fifth month of pregnancy, and due to the increased abdominal load, the pressure on the hip muscles increases when lying down, causing muscle strain and pain over time. Therefore, if a pregnant woman in the fifth month of pregnancy has muscle pain on both sides of the buttocks, she can apply heat and massage appropriately, and take the left side of the bed when sleeping. If the pain is not relieved or even worsens, it is recommended to consult a doctor promptly.