Around 37 weeks of pregnancy, the symptoms of low back pain is a relatively common clinical phenomenon, the main reason for this symptom is due to: 1, lumbar muscle strain, during pregnancy, the pregnant woman’s abdomen increases, the abdomen bulge forward, pregnant women in order to maintain body balance, the muscles and ligaments in the back of the waist will bear excessive pressure, over time will lead to the local soft tissue, the state of chronic strain, causing low back pain 2, pelvic inflammatory disease, pregnant women suffer from pelvic inflammatory disease before pregnancy, after pregnancy due to hormone level changes, pelvic tissue congestion, pelvic pressure and other factors, causing or aggravating the original lumbago symptoms. 3, hydronephrosis, purely limited to the right side of the lumbago symptoms, consider the physiological right hydronephrosis caused by the right side, related to the increased position of the uterus occurred right rotation.