Back pain during pregnancy may be related to the enlargement of the uterus and nerve pulling causing nerve pain. It may also be due to an enlarged abdomen in the middle and late stages of pregnancy, causing a change in body posture, resulting in a prolonged posture of the muscles in the lower back, causing back pain. It may also be due to muscle and ligament strains in the low back or lesions in the internal organs that cause nerve pulling pain. Common diseases include chronic cholecystitis and gallstones, which tend to cause back radiating pain, and peptic ulcers or chronic gastritis, which may also cause back pain. If there are urinary tract infections, tumors, cysts, stones and other factors, they may also cause back pain. If the pain is caused by a change in posture during late pregnancy, localized hot compresses or massage can usually relieve the symptoms.