With the hormonal changes in the body after pregnancy, especially the effects of progesterone, the ligaments of the pelvic joints are loosened, resulting in joint pain. Most of the pain due to this cause falls within the tolerable range. Then again, with the changes of pregnancy, the uterus enlarges, thus making the mother-to-be involuntarily straighten up her body, head and shoulders backward, the abdomen bulges forward, and the waist also straightens forward, which will cause low back pain for a long time. Want to alleviate the discomfort of low back pain during pregnancy, first of all, we must pay attention to pregnancy checkups, regular understanding of the specific situation of pubic bone separation, strengthen physical exercise, often appropriate stretching thighs, enhance muscle and ligament tension and tolerance; second, if the mother-to-be to maintain a certain position for a long time, or the lower back is cold, will aggravate the pain. Expectant mothers can take a more comfortable position, so that the back muscles to relax, such as half lying down, will be a little higher legs, so that the blood return smooth, in order to reduce the edema of the lower limbs. If the pain in the side back is more severe, it is necessary to contact the doctor in time and go to the hospital to check whether there is a urinary tract infection and so on.