During pregnancy, the uterus grows with the growth of the fetus, and the sigmoid colon in the human body occupies the left side of the pelvic cavity, and there is no space on the left side when the uterus grows, so the uterus will gradually rotate and grow to the right. Especially in the middle and late stages of pregnancy, the enlarged uterus will be outside the pelvic cavity, the size of the uterus is huge and will inevitably touch the rectum on the left side of the uterus, because the rectum is originally on the left side of the pelvis, the uterus will be gradually squeezed to the right by the rectum. Because there is a fetus in the uterus, the mass and volume of the uterus is large and will not be easily squeezed to the right side of the uterus right rotation, is a normal physiological phenomenon during pregnancy, do not need to be nervous and worried.