The possible causes of back pain in pregnancy are physiological factors, or due to calcium deficiency, preeclampsia and so on. 1. Physiological factors: after pregnancy, with the growth of the fetus resulting in uterine compression, the increase in the level of HCG in the pregnant woman’s body, resulting in pelvic blood vessel congestion, pelvic ligaments and intervertebral joint ligaments laxity, can cause maternal back pain. 2. Calcium deficiency: After pregnancy, the increased nutritional needs of the mother and fetus can lead to calcium deficiency in the mother, and calcium deficiency in the lumbar vertebrae can lead to the clinical manifestation of back pain in pregnancy. 3. Pre-eclampsia: Patients with pre-eclampsia will experience a certain degree of endometrial shedding, symptoms similar to menstruation, and may also experience back pain and other symptoms. When pregnant with back pain, pregnant women should promptly go to the hospital for further examination to clarify the cause of the disease, and under the guidance of professional doctors for treatment.