In the early stage of pregnancy, because of the hormonal changes in the body, various organs and systems of the organism also produce adaptive changes, thus producing a series of early pregnancy reactions and clinical symptoms. In the first 1-2 weeks of pregnancy, the various tissues and organs of the body have not yet undergone obvious changes, and most pregnant women do not have obvious symptoms of early pregnancy reactions in the first 1-2 weeks, so they do not have symptoms of back pain. As the pregnancy progresses, the fertilized egg slowly develops into an embryo, and the uterus gradually increases in size. When the enlarged uterus presses on the lumbosacral region and the uterosacral ligaments are stretched, some patients may experience lumbosacral pain. As pregnancy progresses further, the enlarged uterus may cause misalignment of the small joints in the spine of the pregnant woman, compressing the spinal nerves or putting the pregnant woman’s lumbar vertebrae in hyperflexion, causing soreness and pain in the lumbar region. Therefore, the lumbar pain in early pregnancy is not obvious and can gradually increase with the progress of pregnancy. It is important to emphasize that the above-mentioned lumbar pain is mild and most pregnant women will be relieved significantly after resting in bed. When the pain in the lower back persists, it is necessary to consult a local hospital to exclude the possibility of organic lesions in the lower back. As mentioned above, most pregnant women do not experience back pain during the first two weeks of pregnancy.