More than five months pregnant with back pain can be caused by a variety of reasons, such as symptoms persist or worsen, it is necessary to consult a doctor to identify the cause of the disease, the most common are the following: First, myofibrillitis, pregnancy is a normal physiological process, can be accompanied by a series of changes in the body’s hormone levels, easy to cause lumbar muscles to appear aseptic inflammation, resulting in pain, activity is limited. Second, changes in abdominal pressure during pregnancy can cause lumbar muscle strain, which can also produce symptoms of lumbar pain. Third, back pain can also occur when there is a lack of calcium, in the process of pregnancy, pregnant women have an increased demand for calcium, most of the calcium is taken by the fetus in the abdomen, if pregnant women do not supplement calcium in a timely manner, it can lead to the occurrence of osteoporosis, which can also cause back pain, it is recommended that the patient in the process of pregnancy in a timely manner for calcium supplements.